ArticlePDF Available

Benefits and Costs of Earthquake Early Warning



Earthquake early warning (EEW) is the rapid detection of earthquakes underway and the alerting of people and infrastructure in harms way. Public warning systems are now operational in Mexico and Japan, and smaller-scale systems deliver alerts to specific users in Turkey, Taiwan, China, Romania, and the United States. The warnings can arrive seconds to minutes before strong shaking, and a review of early warning applications around the world shows this time can be used to reduce the impact of an earthquake by many sectors of society. Individuals can use the alert time to drop, cover, and hold on, reducing injuries and fatalities, or if alert time allows, evacuate hazardous buildings. Train derailments can be reduced, chemical splits limited, patients in hospitals protected, fire ignitions prevented; workers in hazardous environments protected from fall/pinch hazards, reducing head injuries and/or death. It is impossible to complete an exhaustive list of applications and savings generated by a warning system in the United States, but the benefits clearly outweigh the costs. Three lives saved, two semiconductor plants warned, one Bay Area Rapid Transit train slowed, a 1% reduction in nonfatal injuries, and a 0.25% avoidance of gas-related fire damage would each save enough money to pay for 1 year of operation of a public warning system for the entire U.S. West Coast. EEWcould also reduce the number of injuries in earthquakes by more than 50%.
Benefits and Costs of Earthquake Early
by Jennifer A. Strauss and Richard M. Allen
Earthquake early warning (EEW) is the rapid detection of
earthquakes underway and the alerting of people and infra-
structure in harms way. Public warning systems are now opera-
tional in Mexico and Japan, and smaller-scale systems deliver
alerts to specific users in Turkey,Taiwan, China, Romania, and
the United States. The warnings can arrive seconds to minutes
before strong shaking, and a review of early warning applica-
tions around the world shows this time can be used to reduce
the impact of an earthquake by many sectors of society. Indi-
viduals can use the alert time to drop, cover, and hold on,
reducing injuries and fatalities, or if alert time allows, evacuate
hazardous buildings. Train derailments can be reduced, chemi-
cal splits limited, patients in hospitals protected, fire ignitions
prevented; workers in hazardous environments protected from
fall/pinch hazards, reducing head injuries and/or death. It is
impossible to complete an exhaustive list of applications and
savings generated by a warning system in the United States,
but the benefits clearly outweigh the costs. Three lives saved,
two semiconductor plants warned, one Bay Area Rapid Transit
train slowed, a 1% reduction in nonfatal injuries, and a 0.25%
avoidance of gas-related fire damage would each save enough
money to pay for 1 year of operation of a public warning sys-
tem for the entire U.S. West Coast. EEW could also reduce the
number of injuries in earthquakes by more than 50%.
Earthquake early warning (EEW) can provide a few seconds to
a few minutes of warning prior to ground shaking at a given
location. EEW is used publically, and prototypically, in several
countries around the world, with the aim of reducing the dam-
age, costs, and casualties resulting from an earthquake. Actions
taken in response to the alerts range from personal safety ap-
proaches (such as drop, cover, and hold on) to automated con-
trols and situational awareness. In this article, we provide a
summary of the status of EEW around the world for the non-
specialist and provide examples of cost-saving response actions.
This article is intended for prospective users of early warning,
government officials setting policies, and others outside of the
seismological community, illustrating the broad landscape of
mitigation possibilities that early warning provides.
Unlike seismic retrofits, where a direct costbenefit of
damage reduction is readily made, early warning mitigates
many hidden costs that are difficult to monetarily delineate but
are ultimately crucial for long-term resiliency postrupture. At-
tempts to calculate potential annual loss reductions specifically
resulting from EEW actions are difficult, due to the fact that
few outside of the seismological community are aware of the
technical capabilities. For that reason, we here illustrate known
possible savings from EEW and show that EEW can aid in mit-
igation for broad-risk categories, including reducing train de-
railments and chemical spills, isolating radioactive sources,
protecting patients, reducing fall/pinch hazards, and reducing
head injuries and/or death. Though we cannot a priori deter-
mine which individual risks will occur in any given earthquake,
the savings are so significant and so diverse that a robust EEW
system would be a good return on investment. Saving three
individual lives, or alerting two semiconductor plants, or pre-
venting the derailment of one Bay Area Rapid Transit (BART)
train, would each individually save enough money to pay for
one year of operation of the system for the entire U.S. West
Coast. The savings are not limited to just the risks outlined in
this article, even though these alone would be sufficient to jus-
tify the costs of a warning system.
EEW, like warnings for other natural disasters such as torna-
does, hurricanes, and tsunamis, is a forecast of activity that is
imminent. However, unlike hurricane warnings, which can
come days in advance of severe weather, or tsunami warnings,
which build over the course of a few minutes to a few hours
before the tsunami makes landfall, earthquakes have a much
shorter lead time, shorter even than a funnel cloud that starts
spiraling toward the earth. A warning could be just seconds.
This short warning time is a product of the physical proc-
ess of an earthquake rupture. A schematic regional EEWsystem
doi: 10.1785/0220150149 Seismological Research Letters Volume 87, Number 3 May/June 2016 765
is outlined in Figure 1. In essence, EEW uses seismometers to
detect the first signature of an earthquake (Pwave, yellow arc),
to process the waveform information, and to forecast the in-
tensity of shaking that will arrive after the Swave (red arc). For
local EEW installations, the Pwave is detected onsite (i.e., at
the user location), and the difference between the P- and
S-wave arrival times defines the maximum alert time. For
regional networks, the Pwaves are detected by sensors closest
to the epicenter, and estimates are immediately relayed to
earthquake alerting applications (TV, smartphones, radio,
etc.) to provide businesses, citizens, and emergency responders
more advance knowledge of the expected arrival and intensity
of shaking at their location.
Heaton et al. (1985) proposed a model for a computerized
seismic alert network, which laid the groundwork for the EEW
systems in place around the world today. They proposed that
this computer-backed system could protect hazardous chemi-
cals, initiate electrical isolation, and protect fixed-rail transport
systems, hospitals, fire stations, etc. These ideas have now been
tested, and some are operational for several EEW systems
The U.S. Geological Survey (USGS), in partnership with the
University of California at Berkeley, the California Institute of
Technology, and the University of Washington, with support
from the Gordon and Betty Moore Foundation, created an
EEW initiative called ShakeAlert (Fig. 2). This system incor-
porates existing sensors from the California Integrated Seismic
Network and the Pacific Northwest Seismic Network and
sends alerts to a cadre of test usersover 50 groups including
the BART, the cities of San Francisco and Los Angeles, Boeing,
and Intel. It is currently an end-to-end demonstration system,
and conversion to a more redundant and robust production
prototype is underway, with a view toward limited rollouts
Figure 1. Representative illustration of the regional earthquake
early warning concept. Provided by Erin Burkett (U.S. Geological
Survey [USGS]) and Jeff Goertzen (Orange County Register).
Figure 2. (a) ShakeAlert UserDisplay showing a snapshot of
the warning from a simulation of the 1989 Loma Prieta earth-
quake. The red star is the epicentral location, and the yellow
and red circles are the Pand Swavefronts. The key alert infor-
mation is the shaking intensity and time of the Swave (repre-
senting onset of strong shaking) at the users location. This is
the warning at University of California, Berkeley, as indicated by
the location of the blue house icon. The UserDisplay is a java-
based application that can run on any computer and is available
to ShakeAlert test users. (b) MyEEW smartphone app for the
same scenario event. An audible alert with the shaking intensity
at the users location is first received automatically (top of left
screenshot). When the user touches the notification, a simple
screen shows the expected shaking intensity at the userslo-
cation and counts down until the S-wave arrival (middle screen-
shot). By touching the Maplink (top right) a screen with more
information is displayed showing a map of the event and user
location and the magnitude, in addition to the shaking intensity
and countdown (right screenshot).
766 Seismological Research Letters Volume 87, Number 3 May/June 2016
in the near future. The system currently combines single-sta-
tion algorithms (OnSite, Bose et al., 2012), with multistation
approaches (ElarmS, Serdar Kuyuk et al., 2013; Virtual Seis-
mologist, Cua et al., 2009) to provide the quickest and most
accurate alerts possible. Speed is critical for the U.S. West
Coast, because fault lines and their associated hazards coincide
with areas of high population density. Learning from other sys-
tems in operation today worldwide, the ShakeAlert project also
augments the traditional seismic results with Global Position-
ing System (Grapenthin et al., 2014a,b) and Bayesian ap-
proaches (Bose et al., 2014).
ShakeAlert successfully alerted test users for both the 2014
M6.0 South Napa earthquake (Brocher et al., 2015;Dreger
et al., 2015) and the 2014 M5.1 La Habra earthquake (Hauks-
son et al., 2014). The BART system in San Francisco activated
its hazard mitigation protocol, which triggers trains to auto-
matically slow or stop, depending on predetermined condi-
tions. However, no trains were running at 3:20 a.m. when the
Napa earthquake occurred.
Mexico is home to the oldest public EEW system in the
world. The effort began in 1991 with Mexicos strong-motion
accelerometer network, which monitored large subduction
zone earthquakes off of the western coast and alerted citizens
of Mexico City that heavy shaking was on its way. El Sistema
de Alerta Sísmica Mexicano (SASMEX) now sends alerts to
Mexico City, Oaxaca, Acapulco, Chilpancingo, and most re-
cently Morelia via TV, AM/FM radio, National Oceanic and
Atmospheric Administration weather radios, and the Mexican
Hazard Alert System (Espinosa-Aranda and Petel, 2014). In
2009, the 230 registered users for the system were surveyed,
and 91% respondents considered EEW a useful tool for their
institution as a civil protection measure and maintain a positive
view of the system as a whole (Suarez et al., 2009). The city of
Acapulco received 24 s of warning from SASMEX for the
M7.2 Guerrero earthquake on Good Friday, 2014. Mexico
City (situated almost 400 km away) was provided more than
68 s of early warning (see Data and Resources).
The Japanese EEW system successfully alerted several mil-
lion people near the epicenter, providing 1520 s of early warn-
ing, for the 2011 M9.0 Tohoku-Oki earthquake and tsunami
(Fujinawa and Noda, 2013). Ninety percent of the people
alerted were able to take action in response to the warning to
aid in their survival; this high rate of effectiveness was a result
of EEW education and training (Fujinawa and Noda, 2013).
Post-earthquake surveys indicated that almost 80% of respon-
dents were alerted by the EEW and were prompted to take
action. About 82%91% of respondents (the rate varies de-
pending on the survey group) thought favorably of the EEW
system. The system has been in operation since October 2007
and is arguably the most advanced EEW system in the world.
The alerts and automated responses are tied into the high-
speed rail infrastructure, schools, and businesses, and many pri-
vate sector groups provide value-added services to augment the
public alerts provided by the Japan Meteorological Agency.
In June 2015, the Chinese government approved a project
to construct EEW systems in four large regions of the country:
north China, southeast Coastal, the northsouth seismic belt,
and northwestern Xinjiang. The project builds on demonstra-
tions systems that have been running in the Capitol City Zone,
Lanzhou City, and the Fujian Province for several years. The
project will deploy 2000 broadband and strong-motion seismic
stations, an additional 3000 strong-motion sensors, and it
plans to start delivering warning by 2020.
The Seismic eArly warning For EuRope (SAFER) and
Real-time EArthquake risK reducTion (REAKT) projects in-
volved many institutions in Europe funded to explore the pos-
sibility of warning across Europe. A system in Bucharest, above
the deep Vrancea subduction earthquakes, provides a prelimi-
nary shake map to a nuclear research facility within 45sof
the origin time (Zschau et al., 2009). A regional EEW system is
undergoing testing in the Irpinia region east of Naples and
could provide 816 s warning to the city (Zollo et al., 2009).
EEW was implemented in Istanbul in 2002 in response to the
1999 earthquakes. The system provides traffic control for the
Fatih Sultan Mehmet suspension bridge and Marmaray tube
tunnel across the Bosporus Straits as well as the regulator stations
and natural gas valves for the Istanbul Natural Gas Distribution
Network (Alcik et al.,2009). Finally, a demonstration warning
system is operational in Switzerland, and alerts are being deliv-
ered to nuclear power plants (Cauzzi et al.,2014).
Other groups worldwide are also working toward better
earthquake response through early warning. Taiwan is cur-
rently testing its own EEW system, with alerts sent to users in
the railway and disaster-prevention sectors. Hsiao et al. (2009)
discussed that, between 2001 and 2009, 225 alerts were gen-
erated for events greater than M4.5 both inland and off the
coast, with a latency time of 20 s after the origin time of the
earthquake (Hsiao et al., 2009). Israeli Seismic Network scien-
tists are working with University of California, Berkeley, to
implement the Earthquake Alarms Systems (ElarmS) algorithm
in Israel. The system is running in both real time and in real-
time playback modes with a new visualization tool called
ElarmS Visualization System (ElViS). As the technology gains
deeper global penetration, inhabitants of other high-fault-haz-
ard zones will begin looking toward EEW as a possible solution
to their own risk exposure.
Risk exposure refers to the potential loss of life, personal injury,
economic injury, and property damage resulting from natural
hazards by assessing the vulnerability of people, buildings, and
infrastructure to natural hazards (Federal Emergency Manage-
ment Agency [FEMA], 2014). EEW is a tool that can reduce
risk through personal preparedness, situational awareness, and
automated controls. Personal preparedness (including drop,
cover, and hold on) prevents the most common injuries during
an earthquakethose resulting from falling and flying
objectsand increases the safety of the population, particularly
in schools and public places (Zschau et al., 2009;Earthquake
Country Alliance, 2014a). The elderly and persons with dis-
abilities are disproportionally affected by natural disasters
Seismological Research Letters Volume 87, Number 3 May/June 2016 767
and, as such, could most directly benefit from early warnings
and a clear preparedness plan (Brittingham and Wachtendorf,
2013;Earthquake Country Alliance, 2014b). Situational
awareness provided by EEW allows civil protection authorities
advance notice for more rapid and efficient mobilization and
adaptable response (Zschau et al., 2009). Awareness of the lo-
cation, extent, and intensity of the coming shaking allows
responders to assess the impact and their potential next steps.
Protecting critical structures (e.g., hospitals, air traffic con-
trol facilities, schools, and businesses) through EEW-automated
controls allows them to remain operational and is crucial for
long-term resiliency. Earthquake-induced secondary effects
(e.g., fires and industrial accidents) are reduced through the
application of computer-initiated controls that can safeguard
operations, transport systems, and lifelines, thus allowing social
facilities to return to normal as soon as possible (Heaton et al.,
1985;Zschau et al., 2009).
Since 2003, EEW actions in a hospital setting have been imple-
mented and tested at the National Hospital Organization Dis-
aster Medical Center in Japan. Stopping surgery safely and
temporarily disconnecting ventilator tubes are easy and highly
effective ways to prevent fatal errors in the emergency room
during an earthquake (Horiuchi, 2009). Opening doors to pro-
vide egress routes, closing blinds/curtains to minimize glass
debris, and raising awareness of falling hazards aid in reducing
risk to both staff and patients. Securing radioactive sources and
bringing equipment into a safe mode can also effectively pro-
tect people in radiography departments. In the operating room,
staff can stabilize a patient quickly and easily in response to an
early warning. Hazard mitigation plans involving EEW for hos-
pitals must consider the proximity of their staff to the actions
they need to implement as well as the time required to com-
plete said actions for each department independently.
Schools are another sector where staffs need to protect them-
selves as well as a vulnerable population. General protective mea-
sures such as closing curtains to prevent injuries from broken
glass, opening classroom doors to ensure egress, and raising aware-
ness of falling hazards are applicable for schools just as it is for
hospitals. Many schools in Japan are equipped with EEW,and
installation in all schoolsisunderway(Fujinawa and Noda,
2013). Schools receive arrival time and seismic strength informa-
tion and forward alerts to loudspeakers, announcement systems,
and TV receivers in classrooms (Motosaka and Homma, 2009).
On 14 June 2008, the staff of the junior high school in Shiroishi
City (110 km from epicenter of the M6.9 IwateMiyagi Nairiku
earthquake, Japan) took action with 21 s of early warning,
allowing 102 students (including 10 disabled students) to drop,
cover, and hold on to avoided injury.
Police, Fire, and Other Emergency Response Groups
Police, fire, and other emergency-response groups may be in-
volved in rescue efforts and cleanup operations that may be
compromised by aftershocks. Opening firehouse bay doors
in advance of shaking to prevent jamming and activating
municipal Emergency Operations Centers before communica-
tions are lost aids response. Fire and Police departments also
benefit from situational awareness of the forecasted severity of
the shaking. Often, first responders rely on mutual aid from
outside areas to augment their efforts. Simply knowing in ad-
vance which municipalities are going to be affected and which
ones could be called upon for assistance helps to streamline the
process after the event, particularly if communications become
During heavy shaking, an elevator car and counterweight can
move out of alignment becoming jammed. Elevator stoppage
through earthquake detection or early warning protects the
occupants and system. Almost half of the elevators Otis main-
tains in Japan are already equipped with earthquake detectors,
which return the elevators to the ground floor when strong
shaking is detected so passengers can exit (Layne, 2011). Some
16,700 elevators performed an emergency shutdown during the
Tohoku-Oki earthquake in 2011, which meant that first
responders did not have to devote time and resources to rescue
any trapped or injured passengers (Layne, 2011). Other eleva-
tors are linked to EEW systems, allowing safe shutdown before
strong shaking starts. further protecting occupants.
The best-documented example of manufacturing resilience due
to EEW comes from the OKI semiconductor factory in Miyagi
Prefecture, Japan. Early warning alerts trigger isolation of the
hazardous chemical systems and prompt the lithography tables
to move to a safe position in advance of shaking (Allen et al.,
2009). Several automated controls in a manufacturing context
reduce cascading failures, such as shutting off gas valves to pre-
vent secondary hazards and protection of personnel. The Horia
Hulubei National Institute of Physics and Nuclear Engineering,
Romania, prevents cascading failure by automatically securing
their nuclear source (Ionescu et al.,2007).
Other Lifelines
Predetermined risk scenarios used in conjunction with EEW
(Pittore et al., 2014) provide lifelines and emergency respond-
ers a framework of immediate estimates of damage types and
locations. Municipalities could assess activation of mutual-aid
deployment to/from neighboring cities. The Salvation Army
could predetermine which divisions would be impacted under
various earthquake scenarios and implement planning and re-
sponse accordingly (John McKnight, Director of Emergency
and Disaster Services the Salvation Army, personal comm.,
March 2015). Real-time seismic motions for lifelines such as
dams could be compared with predetermined models to inform
disaster prevention actions in the aftermath of an earthquake
(Pagano and Sica, 2012). These actions include the monitoring
of earthquake-induced effects, characterization of dam safety
conditions, and alarming those nearby to reduce exposure.
768 Seismological Research Letters Volume 87, Number 3 May/June 2016
Alerts can also trigger rapid checks of dam safety conditions
with regard to possible collapse scenarios.
Transportation Systems
Transportation systems including airports, railways, and road-
ways are important to safeguard with EEW, not only to protect
passengers but also to ensure the smooth flow of goods needed
for recovery efforts in and out of the impacted area. For air-
ports, personal safety within the terminal would center on
drop, cover, and hold on. Outside the terminal, air traffic con-
trollers with the situational awareness of a coming event can
better manage air traffic. Planes can stop taxiing; baggage han-
dlers can get away from hazardous situations; and planes on
approach can go around until the shaking is over and the run-
ways have been inspected.
The BART in San Francisco is the first transportation sys-
tem in the United States with an end-to-end early warning sys-
tem. BART uses both the ShakeAlert system and on-track
accelerometers (set to trigger at a defined threshold of 0:1g)
to slow and/or stop the trains in safe configurations. On
24 August 2014, the M6.0 South Napa earthquake shook
the Bay Area at 3:20 a.m. The BART operations center in
Oakland, California, received 8 s of early warning before
the S-wave arrival. The system preformed as desired; however,
no actions were ultimately taken, because no trains were run-
ning at the time.
The Shinkansen high-speed trains in Japan have an
impressive track record of performance in earthquakes, due
to engineering controls for the trains and EEW. No passengers
or staff were injured during the Great Tohoku earthquake in
2011, and only one train running in test mode derailed. The S-
wave detector at Cape Kinkazan triggered (120 Gal threshold),
and the emergency brakes were automatically applied to all 33
trains. The first tremors hit the trains nearest the epicenter in
Sendai 912 s after the alert, whereas the strongest shaking
took another minute to arrive (Shimamura and Keyaki, 2013).
Railways also benefit from warnings that arrive too late to
fully complete automated controlsas seen during the 2004
Niigataken Chuetsu earthquake. Train Toki 325 traveled into
the affected region and was jolted by the Pwave without warn-
ing. It received an alarm from the Compact Earthquake De-
tection and Alarm System (UrEDAS) 0.6 s later, and the power
supply was interrupted to slow the train. The driver applied the
emergency brake 1.5 s later after recognizing the Compact
UrEDAS alarm and 1.2 s later the heaviest shaking begannot
nearly enough time to fully slow the train from 204 km=hto a
safe speed. Although the train did ultimately derail, the EEW
provided crucial 1.2 s to slow the train before peak shaking and
thus the derailment was noncatastrophic (Nakamura, 2008).
Drivers on roadways may be unable to identify the shaking
as coming from an earthquake, so alerts on signage can bring
awareness and prompt actions such as preventing motorists
from entering bridges and tunnels. The California Department
of Transportation (Caltrans) made use of an EEW system to
protect workers during the small but hazardous (due to all the
unstable debris) aftershocks of the Loma Prieta earthquake.
The radio receiver at the Caltrans headquarters at the damaged
Cypress St. section of the I-880 freeway in Oakland received a
20 s warning before the M4.5 aftershock on 2 November
1989. In the first six months of operation, the system generated
triggers for all twelve M>3:7aftershocks for which trigger
documentation is preserved, did not generate triggers on any
M3:6aftershocks, and produced only one false trigger (Ba-
kun et al., 1994).
A fully implemented public warning system for the West Coast
of the United States would cost $16.1 million per year above
the current USGS funding levels for the Earthquake Hazards
Program (see Fig. 3), which would finance personnel to run the
system, ongoing improvements and upgrades for the instru-
mentation, and continuing research and development (R&D)
to maintain state-of-the-art alert methods. This does not in-
clude one-time costs of $38 million to increase the station den-
sity of the existing networks and upgrade old seismometers to
current standards (Burkett et al., 2014;Given et al., 2014).
The costs are well defined. The savings are envisioned
through a varied landscape of possibilities. Previous costben-
efit studies in California were assembled before the Internet
and trust in automated controls (Holden, 1989). Now society
not only counts on automation as a part of daily life, but we
have a wealth of information from other countries and their
experience with early warning to inform our choices.
In both the 1989 Loma Prieta and 1994 Northridge earth-
quakes, more than 50% of the injuries were caused by falls and
falling hazards (Shoaf et al., 1998). This includes all the injuries
caused by nonstructural hazards such as falling ceiling tiles,
lighting fixtures, bookcases, and so on. If everyone received
a few seconds of warning, and if everyone dropped, took cover,
and held on, then early warning could reduce the number of
injuries by more than 50% in future earthquakes. Porter et al.
(2006) estimated the cost of injuries in the Northridge earth-
quake to be $1.82.9 billion (in 2005 equivalent dollars), so
EEW could provide $11.5 billion in savings in a future similar
The cost of injuries represents 3%4% of the estimated
$50 billion in direct capital losses and direct business interrup-
tion losses. Taking this 3%4% ratio as indicative of future
events, the economic value of future earthquake injuries
the amount that the U.S. government would deem appropriate
to expend to prevent all such injuriesis on the order of $200
million per year (in 2005 dollars, based on the $4.4 billion
expected annual loss due to earthquakes each year (Porter et al.,
2006). The cost of EEW is $16.1 million per year; a mere 1%
reduction of the injuries in the Northridge earthquake is equiv-
alent to the cost of the system for 1 year (see Fig. 3).
According to FEMAs costbenefit methodology for haz-
ard mitigation projects, the current value of a statistical life in
the United States is $6.6 million (see Fig. 3). Therefore, it
stands to reason that if three deaths per year, on average,
are avoided through implementation of EEW, the system pays
Seismological Research Letters Volume 87, Number 3 May/June 2016 769
for itself (John D. Schelling, Interim Mitigation & Recovery
Section Manager Washington Military Department, Emer-
gency Management Division, testimony before the United
States House Committee on Natural Resources, Subcommittee
on Energy and Mineral Resources, 10 June 2014).
One of the best documented returns on investment for
private industry is that of the OKI semiconductor factory in
Miyagi Prefecture, which experienced $15 million U.S. in losses
due to fire, equipment damage, and loss of productivity in two
moderate earthquakes (M7.1 and 6.4) in 2003. They invested
$600,000 U.S. in retrofits and EEW controls to automatically
shut down hazardous chemical systems and manipulate sensi-
tive equipment into a safe position. In two similar subsequent
earthquakes, the losses were reduced to only $200,000 U.S. (Al-
len et al., 2009), a savings of $7.7 million U.S. per earthquake
(see Fig. 3). There are over 1000 semiconductor companies in
California alone (see Data and Resources), thus protecting just
two of them annually with EEW and retrofits would pay for the
system as a whole.
The Reliability Engineering group for the BART analyzes
passenger flow models for the entire system. Taking Tuesday,
Wednesday, and Thursday averages from 7:00 a.m. to 6:30 p.m.,
3040 trains are moving at any given time, totaling 300400
individual cars in motion (Kevin Copley, Manager of Com-
puter Systems Engineering at BART, personal comm., March
2015). Preventing derailment of one single train during the
workday could save 10 individual rail cars. At a total project
cost of $3.3 million per car, that translates to a possible $33
million of savings, equivalent to 2 years of operation of Shake-
Alert (see Fig. 3). This calculation considers just the cost for
train-car replacement alone; the cost savings of avoiding inju-
ries to passengers would increase the benefit substantially. As an
example, the 12 May 2015 derailment of the Philadelphia,
Pennsylvania, Amtrak train number 188 resulted in 8 fatalities
and 200 injuries at a cost in excess of $9.2 million (National
Transportation Safety Board, 2015).
Other transportation sectors have similarly large assets to
protect. The cost of a single modern airplane, such as the Air-
bus A318 with a list price of $74 million (see Data and Re-
sources), is well in excess of the cost of a 10-car BART
train. Protecting such large capital investments though the use
of an early warning system to divert planes on approach during
heavy shaking could reduce the risk of a costly crash, not only
in the monetary terms for the plane itself, but also for the crew
and passengers who would remain safely on board.
In both the United States and Japan, fire was the single
most destructive seismic agent of damage in the twentieth cen-
tury (Scawthorn et al., 2005). For an M7 earthquake on the
Hayward fault, the loss estimates to fire are around $50 billion
(Charles Scawthorn, after Fires and the Hayward Earthquake
Workshop, written communication, October 2014). This loss
quantity only considers the residential and building replace-
ment value. The total number of ignitions is estimated to be
around 1000, with 25% of those stemming from gas connec-
tions and underground lines. Some gas valves during the 1994
Northridge earthquake had seismic shut-offs installed, which
helped reduce ignition (Scawthorn et al., 2005); implementa-
tion of EEW-based shut-offs would be able to boost their effect.
If only one quarter of 1% (0.25%) of the damage due to gas-
related ignitions could be prevented by early warning, a savings
of $31.25 million could be realized (see Fig. 3).
Figure 3. Comparison of the cost of running a U.S. West Coast early warning system (orange) with some of the identifiable savings
(green). All disks are scaled relative to the white disk representing $10 million.
770 Seismological Research Letters Volume 87, Number 3 May/June 2016
Implementation of EEW systems is increasing around the
world: Mexico, Japan, Europe, Israel, Taiwan, China, and now
the United States, all have systems and provide alerts to users.
There are now real-life demonstrations of the benefits of EEW.
Building occupants in Mexico are able to evacuate structures
that are likely to collapse in an earthquake. School children
took shelter during the 2011 Tohoku-Oki earthquake. Trains
can be slowed to reduce the risk of derailment. Factory workers
using heavy machinery can reduce crush injuries or pinch haz-
ards with advanced notice of shaking. This is not an exhaustive
list, but rather a snapshot of the critical lifelines and industries
that could benefit from early warning.
EEW is not a panacea, nor a replacement for robust infra-
structure or seismic retrofits. EEW is a tool that augments risk
mitigation efforts both before and after a rupture. The benefits
clearly outweigh the costs. Three lives saved, two semiconduc-
tor plants warned, one BARTtrain slowed, a 1% reduction in
nonfatal injuries, a 0.25% avoidance in gas-related fire damage,
could each in theory save enough money to pay for one year of
operation of the system for the entire U.S. West Coast. EEW
could also reduce the number of injuries in earthquakes by
more than 50%.
These specific examples represent just the beginning of
what will be a much longer list of possible applications for
EEW.AsEEW technology becomes better known and under-
stood, as EEW system are further implemented around the
world, and as our world becomes ever more interconnected
and automated, more and more businesses will be able to iden-
tify appropriate applications to safeguard their own assets. It
therefore seems clear that the savings substantially outweigh
the costs of implementing EEW.
The video of the early warning alert can be found at https:// (last accessed Feb-
ruary 2016). The semiconductor companies in California list-
ing can be found at
(last accessed March 2015). Airbus A318 listing can be found
(last accessed April 2015).
dation through Grant Number GBMF3024 to University of
California, Berkeley, and the U.S. Geological Survey (USGS)/
National Earthquake Hazards Reduction Program Award
G12AC20348. The authors would also like to thank Kevin
Copley at Bay Area Rapid Transit (BART), John McKnight
of The Salvation Army, and Margaret Vinci at Caltech for
their insight.
Alcik, H., O. Ozel, N. Apaydin, and M. Erdik (2009). A study on warning
algorithms for Istanbul earthquake early warning system, Geophys.
Res. Lett. 36, L00B05, doi: 10.1029/2008GL036659.
Allen, R. M., P. Gasparini, O. Kamigaichi, and M. Bose (2009). The sta-
tus of earthquake early warning around the world: An introductory
overview, Seismol. Res. Lett. 80, 682693.
Early warning system for aftershocks, Bull.Seismol.Soc.Am.
84, 359365.
Bose, M., R. M. Allen, H. Brown, G. Gua, M. Fischer, E. Hauksson, T.
Heaton, M. Hellweg, M. Liukis, D. Neuhauser, et al. (2014). CISN
ShakeAlert: An earthquake early warning demonstration system for
California, in Early Warning for Geological Disasters, F. Wenzel and
J. Zschau (Editors), Springer, Berlin, Germany, 4969.
Bose, M., T. Heaton, and E. Hauksson (2012). Rapid estimation of earth-
quake source and ground-motion parameters for earthquake early
warning using data from a single three-component broadband or
strong-motion sensor, Bull. Seismol. Soc. Am. 102, 738750.
Brittingham, R., and T. Wachtendorf (2013). The effect of situated access
on people with disabilities: An examination of sheltering and tem-
porary housing after the 2011 Japan earthquake and tsunami,
Earthq. Spectra 29, S433S455.
Brocher, T. M., A. S. Baltay, J. L. Hardebeck, F. F. Pollitz, J. R. Murray, A.
L. Llenos, D. P. Schwartz, J. L. Blair, D. J. Ponti, J. J. Lienkaemper,
et al. (2015). The Mw6.0 24 August 2014 South Napa earthquake,
Seismol. Res. Lett. 86, 309326.
Burkett, E. R., D. D. Given, and L. M. Jones (2014). ShakeAlertAn
Earthquake Early Warning System for the United States West Coast,
U.S. Department of the Interior, U.S. Geological Survey, factsheet
Cauzzi, C., Y. Behr, J. Clinton, S. Wiemer, J. Wössner, M. Caprio, G.
Cua, T. Le Guenan, J. Douglas, and S. Auclair (2014). Final report
on the feasibility study and initial EEW implementation efforts for
nuclear power plants in Switzerland, 28 pp.
Cua, G., M. Fischer, T. Heaton, and S. Wiemer (2009). Real-time per-
formance of the virtual seismologist earthquake early warning algo-
rithm in southern California, Seismol. Res. Lett. 80, 740747.
Dreger, D. S., M. Huang, A. Rodgers, T. Taira, and K. Wooddell (2015).
Kinematic finite-source model for the 24 August 2014 South Napa,
California, earthquake from joint inversion of seismic, GPS, and
InSAR data, Seismol. Res. Lett. 86, 327334.
Earthquake Country Alliance (2014a). How to Protect Yourself During an
#whattodo (last accessed November 2015).
Earthquake Country Alliance (2014b). Earthquake Preparedness Guide
for People with Disabilities and Other Access or Functional Needs,
Guide_Disabilities_AFN.pdf (last accessed November 2015).
Espinosa-Aranda, J. M., and E. Petel (2014). Earthquake alerts: From
black magic to science and engineering, Third International
Conference on Earthquake Early Warning, UC Berkeley, Berkeley,
California, 35 September 2014.
Federal Emergency Management Agency (FEMA) (2014). Hazard mit-
igation planning risk assessment.
Fujinawa, Y., and Y. Noda (2013). Japans earthquake early warning sys-
tem on 11 March 2011: Performance, shortcomings, and changes,
Earthq. Spectra 29, S341S368.
Given, D. D., E. S. Cochran, T. H. Heaton, E. Hauksson, R. M. Allen, P.
Hellweg, J. Vidale, and P. Bodin (2014). Technical implementation
plan for the ShakeAlert production systemAn Earthquake Early
Warning system for the West Coast of the United States, U.S. Geol.
Surv. Open-File Rept. 2014-1097, 25 pp, doi: 10.3133/ofr20141097.
Grapenthin, R., I. Johanson, and R. M. Allen (2014a). The 2014 Mw6.0
Napa earthquake, California: Observations from real-time GPS-en-
hanced earthquake early warning, Geophys. Res. Lett. 41, 82698276.
Seismological Research Letters Volume 87, Number 3 May/June 2016 771
Grapenthin, R., I. A. Johanson, and R. M. Allen (2014b). Operational
real-time GPS-enhanced earthquake early warning, J. Geophys. Res.
119, 79447965.
Hauksson, E., A. Guarino, K. Hutton, N. Scheckel, R. Graves, K. Hudnut,
L. Jones, and K. Feltzer (2014). CISN/SCSC Executive Summary, (last accessed December 2014).
Heaton, T. H., N. Series, and N. May (1985). A model for a seismic
computerized alert network, Science 228, 987990.
Holden, R. (1989). Technical and Economic Feasibility of an Earthquake
Early Warning System in California, Special Publication: California
Division of Mines and Geology, Sacramento, California.
Horiuchi, Y. (2009). Earthquake early warning hospital applications,
J. Disast. Res. 4, 237241.
Hsiao, N.-C., Y.-M. Wu, T.-C. Shin, L. Zhao, and T.-L. Teng (2009).
Development of earthquake early warning system in Taiwan, Geo-
phys. Res. Lett. 36, L00B02, doi: 10.1029/2008GL036596.
Ionescu, C., M. Bose, F. Wenzel, A. Marmureanu, A. Grigore, and G. Mar-
mureanu (2007). Early warning system for deep Vrancea (Romania)
earthquakes, in Earthquake Early Warning Systems, P. Gasparini, G.
Manfredi, and J. Zschau (Editors), 343349.
Layne, R. (2011). Japan Quake: How Otis Rose to the Challenge, Bloom-
berg Business, 24 March,
content/11_14/b4222020340761.htm (last accessed February 2016).
Motosaka, M., and M. Homma (2009). Earthquake early warning system
application for school disaster prevention, 4, no. 4, 229236.
Nakamura, Y. (2008). First actual P-wave alarm systems and examples of
disaster prevention by them, 14th World Conference on Earthquake
Engineering, Beijing, China, 1217 October 2008.
National Transportation Safety Board (2015). Preliminary Rept,http://
Preliminary.aspx (last accessed February 2016).
Pagano, L., and S. Sica (2012). Earthquake early warning for earth dams:
Concepts and objectives, Nat. Hazards 66, 303318.
Pittore, M., D. Bindi, J. Stankiewicz, A. Oth, M. Wieland, T. Boxberger,
and S. Parolai (2014). Toward a loss-driven earthquake early warn-
ing and rapid response system for Kyrgyzstan (central Asia), Seismol.
Res. Lett. 85, 13281340.
Porter, K., K. Shoaf, and H. Seligson (2006). Value of injuries in the
Northridge earthquake, Earthq. Spectra 22, 555563.
Scawthorn, C., J. M. Eidinger, and A. J. Schiff (Editors) (2005). Fire Fol-
lowing Earthquake, ASCE Publications, 352 pp.
Serdar Kuyuk, H., R. M. Allen, H. Brown, M. Hellweg, I. Henson, and
D. Neuhauser (2013). Designing a network-based earthquake early
warning algorithm for California: ElarmS-2, Bull. Seismol. Soc. Am.
104, 162173.
Shimamura, M., and T. Keyaki (2013). How Japans bullet trains survived
the 2011 Great Tohoku earthquake, Proc. Eastern Asia Soc. Trans-
port. Stud. 9, 49.
Shoaf, K. I., L. H. Nguyen, H. R. Sareen, and L. B. Bourque (1998).
Injuries as a result of California earthquakes in the past decade,
Disasters 22, 218235.
Suarez, G., D. Novelo, and E. Mansilla (2009). Performance evaluation of
the seismic alert system (SAS) in Mexico City: A seismological and a
social perspective, Seismol. Res. Lett. 80, 707716.
Zollo, A., G. Iannaccone, M. Lancieri, L. Cantore, V. Convertito, A.
Emolo, G. Festa, F. Gallovič, M. Vassallo, C. Martino, et al.
(2009). Earthquake early warning system in southern Italy: Method-
ologies and performance evaluation, Geophys. Res. Lett. 36, L00B07,
doi: 10.1029/2008GL036689.
Zschau, J., P. Gasparini, and G. Papadopoulos (2009). Seismic Early Warn-
ing for Europe Final Rept,
dissemination/SAFER_Final_Report.pdf (last accessed February 2016).
Jennifer A. Strauss
Richard M. Allen
Berkeley Seismological Laboratory
University of California, Berkeley
215 McCone Hall, Number 4760
Berkeley, California 94720 U.S.A.
Published Online 23 March 2016
772 Seismological Research Letters Volume 87, Number 3 May/June 2016
... Earthquake early warning (EEW) systems detect earthquakes in the initial phases of fault rupture, rapidly estimate source parameters and/or the intensity of the resulting ground motion, and alert end users before they experience the intense shaking that might cause damage and financial/human losses. A review of worldwide EEW applications shows that the warning time facilitated by an EEW system (typically seconds to tens of seconds, depending on the source-to-site distances) can potentially reduce the impact of an earthquake across many sectors of society, although inherent, practical limitations exist (e.g., [1][2][3]). ...
... There are nine bays in the longitudinal direction, with a uniform bay length of 3.5 m; three bays with a length of 4.0 m for the classrooms and 2.0 m for the corridor are assumed in the short direction of the building. This results in an overall longitudinal plan dimension of 31.0 m, a short plan dimension of 10.0 m, and a total floor area of 310 m. 2 Each floor comprises four classrooms with an area of 56 m 2 each, a staircase, and a 2.0m-wide corridor extending along the longitudinal direction of the floor. These geometric features are illustrated in Fig. 3, which provides a plan view of the developed archetype building. ...
Full-text available
Earthquake early warning (EEW) is currently deemed a credible approach to seismic resilience enhancement in modern societies, especially if part of a more holistic earthquake mitigation strategy involving other risk reduction tools such as structural upgrading/retrofit. Yet, there remains a strong need to 1) assess the feasibility of EEW in various seismotectonic contexts, considering specific target applications/end users; and 2) develop next-generation decision-support systems relying on interpretable probabilistic impact-based estimates toward more risk-informed decision-making on EEW installation/alert triggering. These challenges are addressed in this paper, which showcases a series of recent significant EEW contributions by the authors. First, we present the results of a state-of-the-art feasibility study for EEW in schools performed across the Patras region of Greece, attempting to spatially combine traditional seismologically-driven EEW decision criteria (i.e., warning time) with proxy risk-oriented measures for earthquake impact (i.e., building fragility and the number of exposed school students). These results show that, under certain conditions, EEW could be effective for the schools in the considered case-study region. We then demonstrate an advanced end-user-centred approach for improved risk-informed decision-making on triggering EEW alerts. The proposed methodology integrates earthquake-engineering-related seismic performance assessment procedures and metrics with multi-criteria decision-making (MCDM) within an end-to-end probabilistic framework. The performance-based earthquake engineering component of such a framework facilitates the computation of various damage/loss estimates (e.g., repair cost, downtime, and casualties) by combining target-structure-specific models of seismic response, fragility, and vulnerability with real-time ground-shaking estimates. Additionally, the incorporated MCDM methodology enables explicit consideration of end-user preferences (importance) towards the estimated consequences in the context of alert issuance. The developed approach is demonstrated using an archetype school building for the case-study region, for which we specifically investigate the optimal decision (i.e., “trigger” or “don't trigger” an EEW alert) across a range of ground-motion intensity measures. We find that the best action for a given level of ground shaking can vary as a function of stakeholder preferences.
... Earthquake early warning (EEW) systems have been active in some parts of the world for decades; these systems typically use sensors to detect the primary earthquake waves (which move faster but tend to be non-damaging) and then send an alert to users before the dangerous secondary waves (which tend to cause the damage) reach them. While these systems have potential benefits, they also have considerable costs (Strauss and Allen, 2016). Recent technological advancements mean these systems are becoming more common and reaching a larger number of people. ...
Full-text available
Introduction: Aotearoa New Zealand (NZ) experiences frequent earthquakes, with a history of damaging and fatal events, but currently does not have a national, official earthquake early warning (EEW) system. Since April of 2021, Google's Android Earthquake Alert System has operated independently in NZ. While recent work has identified general public support for such a system, it is important to assess public knowledge of EEW as well as typical responses to receiving an alert. The protective actions “Drop, cover, and hold” are recommended and taught in NZ and previous research found strong intentions to undertake these and other protective actions in response to an alert. Method: However, it is important to explore a range of responses to these novel EEWs, including how much people know about them, what actions they took in response to the warning, and their overall judgment of the system including its usefulness. We undertook surveys following two widely received alerts from the Android Earthquake Alert System to assess public knowledge, perceptions, and responses to these alerts with a total sample size of 3,150. Results: While most participants who received the alert found it useful, knowledge of both EEW generally and the Android System specifically was low and few participants used the time to protect themselves from shaking. Discussion: These findings reiterate the importance of education and communication around a warning system, so that the public know how to act when they receive an alert.
... Earthquake early warning (EEW) systems are implemented to quickly predict earthquake information (location, magnitude, and potential impact) for areas where damaging seismic waves have not arrived. Although the lead time for the warning information is often in the order of seconds, this lead time is still invaluable in preparing for life-saving measures and arranging emergency responses for important engineering facilities and systems (Allen & Melgar, 2019;Strauss & Allen, 2016). Since the establishment of the Japanese Urgent Earthquake Detection and Alarm System for the Shinkansen by Nakamura in the 1980s (Nakamura, 1988;Nakamura & Saita, 2007), there have been more than a dozen EEW systems built or being built worldwide (Allen & Melgar, 2019;Cremen & Galasso, with earthquake intensity and damage, and they are often used in EEW systems to predict subsequent intensity or potential damage after an earthquake event is identified (Festa et al., 2018;Hsu et al., 2018;Satriano et al., 2011). ...
A rapid and accurate estimate of earthquake damage is a key component in a successful earthquake early warning (EEW) system. The cumulative absolute velocity (CAV) is an important and widely used parameter to measure ground motion intensity, but it cannot be correctly estimated via the traditional approach with the limited information available in typical EEW systems. Therefore , current EEW systems cannot effectively use CAV to predict earthquake damage. Herein, a CAV prediction model (DLcav) based on convolutional neu-ral networks was proposed for EEW systems. DLcav is an end-to-end solution to continuously predict CAV using arriving seismic waves of increasing length and supplemented with additional auxiliary information. The effectiveness of DLcav to predict CAV was tested based on Japanese ground motion records, and the generalization ability of DLcav was assessed using the ground motion records from Chile. The results demonstrate that DLcav can rapidly predict CAV with good accuracy, which will help better estimate earthquake damage in EEW systems.
... This increases preparedness time prior to earthquake occurrence in a community and improve the efficiency of emergency management. However, the growth of seismic observation weakens as such projects can cost millions of dollars (Strauss and Allen, 2019) and usually heavy and bulky with complex maintenance procedures. For instance, a complete seismic monitoring system for the West Coast of the United States would cost 16.1 million dollars per year and cost to increase number of stations as well to upgrade the system is 38 million dollars (Strauss and Allen, 2019). ...
Full-text available
Seismic monitoring networks are the crucial elements in strong motion seismology for effective risk reduction. Low scale lateral variation of high intensity ground movement caused by earthquakes will be detected more effectively with densely located networks. However, the limitations of developing such project are rooted in expensive costs associated with the construction and installation in addition to bulky size of the conventional seismic observation system. Recently, micro-electromechanical system (MEMS) has being recognized in the applications of seismological and earthquake engineering due to the high precision obtained in these micron size semiconductor instruments and cheaper alternative for traditional seismic detector. ADXL345 is a type of digital triaxial MEMS accelerometer that is ideal for measurement of low-frequency vibrations and static accelerations of gravity, which makes it suitable for ground motion detection. Thus, this study aims at calibrating ADXL345 sensor that is required as sensing component in an affordable earthquake monitoring system with the Earthquake Benchmarking System (Penanda Aras Gempa Bumi, PAG) available in the inventory of Department of Mineral and Geoscience Malaysia, Sabah. Soil vibrations in EW (east-west or x-axis), NS (north-south or y-axis), and UD (up-down or z-axis) directions during random forces hit on the surface are recorded by both accelerometers. Acceleration magnitudes recorded by PAG and ADXL345 are extracted and data exploration is performed. Predominantly, ADXL345 measurements in horizontal and vertical ground movements are on a higher scale than the reference device. Subsequently, evaluation by using descriptive statistical analysis is chosen to produce numerical equations for data correction operations. İmplementation of the mathematical functions in ADXL345 for observing land movements in EW, NS, and UD directions resulted in decreasing the range values of output readings. Higher approximation of magnitudes of ground motion with the PAG system is achieved.
... The EEW has been proven to be highly effective in reducing human casualties since the 2000s (Allen and Melgar, 2019). The aim of EEW is to notify the public about imminent strong ground shaking and to protect the people, public systems, and national infrastructure (Heaton, 1985;Strauss and Allen, 2016;Allen and Melgar, 2019). Therefore, EEW systems were operational or/and being tested in over 20 countries (Cremen and Galasso, 2020). ...
Full-text available
Earthquake Early Warning (EEW) is an alert system, based on seismic wave propagation theory, to reduce human casualties. EEW systems mainly utilize technologies through both network-based and on-site methods. The network-based method estimates the hypocenter and magnitude of an earthquake using data from multiple seismic stations, while the on-site method predicts the intensity measures from a single seismic station. Therefore, the on-site method reduces the lead time compared to the network-based method but is less accurate. To increase the accuracy of on-site EEW, our system was designed with a hybrid method, which included machine learning algorithms. At this time, machine learning was used to increase the accuracy of the initial P-wave identification rate. Additionally, a new approach using a nearby seismic station, called the 1+ α method, was proposed to reduce false alarms. In this study, an on-site EEW trial operation was performed to evaluate its performance. The warning cases for small and large events were reviewed and the possibility of stable alert decisions was confirmed.
... The enduser stakeholders can then initiate their emergency management protocols and warn individuals to take precautionary action (e.g. drop cover hold-on), depending upon the estimated length of time following the alert until strong ground shaking is expected at their location; the end-user stakeholders can activate emergency responder protocols (e.g. opening fire station doors, warning hospitals of potential casualties etc.); place systems into fail-safe mode or initiate slowdown of horizontal transit systems [14,15]. Such actions can, in turn, reduce downtime and support rapid business and service delivery recovery [16]. ...
Full-text available
Facilities managers have a key role to play in improving organisational resilience to disaster events. However, there is currently limited support available to help them understand and systematically manage related issues. At the strategic level, they need to understand the physical, operational, and organisational risks associated with individual and cascading events. At the operational level, they need to develop mitigation interventions to reduce and manage these risks. This paper discusses results from the TURNkey project, which developed a forecasting, early warning and consequence response platform to assist decision-makers prepare for, respond to and recover from a potential earthquake event. It looks at this disaster management platform through the lens of business, outlining the opportunities and challenges facilities managers face when using it to manage organisational resilience. First, the paper presents an overview of the TURNkey platform and describes a series of end-user use cases that were developed to identify the key business issues the platform needed to address. The paper then reports the results of a hypothetical case study undertaken as part of a regional earthquake simulation to show how the outputs from the TURNkey FWCR platform can be integrated into existing resilience plans. The paper concludes by highlighting outstanding integration issues and the role that facilities managers can play in helping resolve them. Although the paper draws on evidence from earthquake disasters, its findings and conclusions are generic, and applicable to any disaster event.
... We use the same domain and magnitude constraints as our inversion dataset for the validation dataset. We chose not to include events that occurred prior to 1 January 2000 in our validation dataset because recent events have nearly 3 times as many stations contributing data compared with events in the 1990s due to the explosion of broadband stations in California for earthquake early warning (e.g., Strauss & Allen, 2016). ...
Full-text available
Adjoint waveform tomography (AWT) sits at the cutting edge of seismic tomography on local, regional, and global scales. However, the choice in starting model may have a significant impact on the final inversion results. In this paper, we present 3 AWT models of California that are based on different starting models. We chose three models that were inverted at different scales: SPiRaL, a global travel‐time tomography model (Simmons et al., 2021, 10.1093/gji/ggab277), CSEM_NA, a regional adjoint tomography model of North America and the North Atlantic (Krischer et al., 2018, 10.1029/2017JB015289), and WUS256, a regional adjoint tomography model of the western US (Rodgers et al., 2022, We then inverted three AWT models using the same source and receiver set. We ran each model over three period bands: 30–100 s, 25–100 s, and 20–80 s. Once the iterations were finalized, we used five methods of testing model similarity in both the model and data space. We conclude that the choice of starting model has a minimal impact on long wavelength models if an appropriate multi‐scale inversion approach is used.
Full-text available
An earthquake early warning system (EEWS) can provide valuable alerts before the destructive seismic waves arrive. This warning time can allow the adoption of protective measures by the population, which can translate into reduced casualties and economic savings. In the last centuries, Portugal was struck by several strong earthquakes (e.g., 1755 M ~ 8.5 Lisbon, 1969 M7.8 Algarve), whose magnitude and epicentre might allow large warning times. In this study, a probabilistic seismic hazard analysis (PSHA) model was used to generate a large stochastic event set for mainland Portugal, and the expected human impact (i.e., fatalities and injured) were estimated for each seismic event with and without the consideration of an EEWS. We evaluated different options for the reduction in the casualties considering the duration of the warning time, human reaction time, and the size of the buildings. The potential reduction in the human impact was converted into an economic benefit considering hospitalization costs and the statistical value of a human life in Portugal. The results indicate that such a system could significantly reduce the human and related economic losses in the Southwest of the country.
Full-text available
The United States is extremely vulnerable to catastrophic earthquakes. More than 143 million Americans may be threatened by damaging earthquakes in the next 50 years. This thesis argues that the United States is unprepared for the most catastrophic earthquakes the country faces today. Earthquake early warning systems are a major solution in practice to reduce economic risk, to protect property and the environment, and to save lives. Other countries have already built earthquake early warning systems, but only after they suffered devastating earthquakes. In the United States, ShakeAlert is the available solution, but it only operates on a test basis in California and still lacks sufficient capability and sustained funding to become operational. This thesis applies an input-output model of political systems theory to analyze how the National Earthquake Hazards Reduction Program, which controls the development of ShakeAlert, functions in the United States. Using this model provides a framework for a discourse of the analysis to determine how the consequences of catastrophic earthquakes shape our decisions and policies for ShakeAlert. This thesis also examines what changes are required within our political system for ShakeAlert to launch as quickly as possible on a national scale and to allow for its sustained integration within the American preparedness culture. Perhaps most importantly, the implementation of ShakeAlert will help prepare the people, businesses, infrastructure, economies, and communities, hopefully before the next significant earthquake impacts the United States. Will the United States have to experience a devastating earthquake before implementing a solution that is recognized to save lives?
Timely alerts sent through earthquake early warning (EEW) programs allow those alerted to take protective actions to mitigate their risk from potentially damaging shaking. Over the past few years, ShakeAlert, the EEW program focused on the west coast of the contiguous United States, has grown, alerting communities within California, Oregon, and Washington about earthquakes where damaging shaking is expected. ShakeAlert uses a set of algorithms including the point-source algorithm, earthquake point-source integrated code (EPIC), to determine the location, magnitude, and origin time of potential earthquakes. Although EPIC produces low-latency and low error solutions for many events originating within the seismic network on land, numerous recent small earthquakes rupturing offshore of northern California have EPIC location solutions with high error (>50 km compared to USGS locations). Because most events are occurring offshore, there is a limited number of stations that can trigger and contribute information in a timely manner for use in EEW. To better constrain location solutions in this region, we propose to include information about contemporary past seismicity into EPIC’s grid-search algorithm through a Bayesian framework. This prior information layer downweights high error locations where EPIC’s proposed event location coincides with an area of low prior seismicity in preference for locations with a similar level of data fit that also have higher past seismicity. This addition to EPIC lowers the mean location error offshore northern California from 58 to 14 km.
Full-text available
Online Material: Movie of wave propagation, GPS coseismic displacements, rupture velocity, waveform comparisons, geologic and 3D seismic structure, and moment rate functions. On 24 August 2014 at 10:20:44.06 UTC, a large earthquake struck the north San Francisco Bay region, approximately 10 km south‐southwest of Napa, California, causing local damage in older wood frame and masonry buildings, road surfaces, sidewalks, and masonry wall structures (Bray et al. , 2014). Using long‐period (50–20 s) three‐component, complete displacement records, the Berkeley Seismological Laboratory (BSL) estimated the scalar seismic moment at 1.32×1018 N·m for a depth of 11 km, corresponding to a moment magnitude of M w 6.0. The strike/dip/rake from the seismic moment tensor solution was 155°/82°/−172°, which is in overall agreement with the trends of structures comprising the West Napa fault system (Fig. 1). Geologic mapping revealed an approximately 14 km long surface rupture with 40–45 cm maximum observed slip on a complex multibranched fault system (Bray et al. , 2014; Earthquake Engineering Research Institute [EERI], 2014; Mike Oskin and Alex Morelan, written comm., 2014). The largest surface offsets were found on a northwest‐striking trend located approximately 1.8 km west of the mapped West Napa fault. Aftershocks are generally located west of the western branch of the surface fault, which had the largest offsets, and indicate a westward dip of the primary fault plane (Fig. 2). Figure 1. Locations of Berkeley Digital Seismic Network (BDSN) stations are shown as labeled squares. Plate Boundary Observatory (PBO) Global Positioning System (GPS) sites are shown as circles, and the positions of Interferometric Synthetic Aperture Radar (InSAR) returns are small gray squares. San Francisco and Napa Valley are indicated by SF and NV. The Berkeley Seismological Laboratory focal mechanism is shown, and the thick line shows the mapped surface trace (EERI, 2014). Figure 2. (a) Coseismic fault‐slip model based on the joint inversion of …
Full-text available
A well-developed public earthquake early warning (EEW) system has been operating in Japan since October 2007. At the time of the 2011 Tohoku-oki earthquake and tsunami (also known as 3.11), several million people near the epicenter received theEEWabout 15 to 20 seconds before the most severe shaking occurred, and many more people in surrounding districts had greater lead time before less severe shaking started. Some 90% of these people were able to take advance actions to save their own lives and those of family members or to take other actions according to prior planning. Some actions were taken based on intuitive responses to the alerts. This high rate of effectiveness is assured to be the result of education regarding the EEW system, both in schools and in society at large. In spite of some shortcomings, the proven effectiveness of EEW has led Japan to strengthen the already extensive seismic- and tsunami-monitoring networks offshore, east of the Japan island arc at 150 sites, and to provide a special terminal for advanced uses of EEW in schools with more than 53,000 students. Efforts are also underway to improve analysis and dissemination schemes.
Full-text available
Recently, progress has been made to demonstrate feasibility and benefits of including real-time GPS (rtGPS) in earthquake early warning and rapid response systems. Most concepts, however, have yet to be integrated into operational environments. The Berkeley Seismological Laboratory runs an rtGPS based finite fault inversion scheme in real-time. This system (G-larmS) detected the 2014 Mw 6.0 South Napa earthquake in California. We review G-larmS’ performance during this event and 13 aftershocks and present rtGPS observations and real-time modeling results for the main shock. The first distributed slip model and magnitude estimates were available 24 s after the event origin time, which, after optimizations, was reduced to 14 s (≈8 s S-wave travel time, ≈6 s data latency). G-larmS’ solutions for the aftershocks (that had no measurable surface displacements) demonstrate that, in combination with the seismic early warning magnitude, Mw 6.0 is our current resolution limit.
Full-text available
Over the last decade, increasing attention has been paid by the international community to the topic of earthquake early warning (EEW) systems, as a viable solution to protect specific hazard‐prone targets (major cities or critical infrastructure) against harmful seismic events. The aim of the EEW system is to detect the occurrence of an earthquake and to determine its relevant characteristics (such as location and magnitude) early enough to predict the ground shaking at the target site before the S ‐wave arrival. Possible emergency protocols that can be activated upon event detection range from slowing down or stopping rail traffic (Nakamura, 2004; Horiuchi et al. , 2005; Espinosa‐Aranda et al. , 2011), safely shutting down or activating protective measure of critical infrastructures such as nuclear power plants (Saita et al. , 2008), to broadcasting alerts to the general public (Wenzel and Lungu, 2000; Lee and Espinosa‐Aranda, 2002; Allen and Kanamori, 2003; Horiuchi et al. , 2005; Wu et al. , 2007). Only few systems have been actually implemented and are currently operational. Examples of regional applications are the systems operating in California, Japan, and Taiwan, whereas targeted systems have been developed, for instance, in Mexico, Irpinia (Italy), and Vrancea (Romania). We refer the interested readers to the comprehensive references in Wenzel and Zschau (2014). Despite the potential benefits of EEW system, several factors so far hindered their widespread application especially in economically developing countries. When the distance between the seismic sources and the exposed target is too short for instance, or there is no technological infrastructure supporting real‐time, automatic operations, the information provided by the EEW system cannot be exploited for pre‐event actions. In these cases, which occur remarkably often in many seismic regions, the level of ground shaking predicted by the system can still be used as input …
Full-text available
Moment magnitudes for large earthquakes (Mw≥7.0) derived in real-time from near field seismic data can be underestimated due to instrument limitations, ground tilting, and saturation of frequency/amplitude-magnitude relationships. Real-time high-rate GPS resolves the build-up of static surface displacements with the S-Wave arrival (assuming non-supershear rupture), thus enabling the estimation of slip on a finite fault and the event's geodetic moment. Recently, a range of high-rate GPS strategies has been demonstrated on off-line data. Here, we present the first operational system for real-time GPS-enhanced earthquake early warning as implemented at the Berkeley Seismological Laboratory (BSL) and currently analyzing real-time data for Northern California. The BSL generates real-time position estimates operationally using data from 62 GPS stations in Northern California. A fully triangulated network defines 170+ station pairs processed with the software trackRT. The BSL uses G-larmS, the Geodetic Alarm System, to analyze these positioning time series, and determine static offsets and pre-event quality parameters. G-larmS derives and broadcasts finite fault and magnitude information through least-squares inversion of the static offsets for slip based on a-priori fault orientation and location information. This system tightly integrates seismic alarm systems (CISN-ShakeAlert, ElarmS-2) as it uses their P-wave detections to trigger its processing; quality control runs continuously. We use a synthetic Hayward Fault earthquake scenario on real-time streams to demonstrate recovery of slip and magnitude. Re-analysis of the Mw7.2 El Mayor-Cucapah earthquake tests the impact of dynamic motions on offset estimation. Using these test cases, we explore sensitivities to disturbances of a-priori constraints (origin time, location, fault strike/dip).
Full-text available
The California Integrated Seismic Network (CISN) is developing an earthquake early warning (EEW) demonstration system for the state of California. Within this CISN ShakeAlert project, three algorithms are being tested, one of which is the network-based Earthquake Alarm Systems (ElarmS) EEW system. Over the last three years, the ElarmS algorithms have undergone a large-scale reassessment and have been recoded to solve technological and methodological challenges. The improved algorithms in the new production-grade version of the ElarmS version 2 (referred to as ElarmS-2 or E2) code maximize the current seismic network's configuration, hardware, and software performance capabilities, improving both the speed of the early warning processing and the accuracy of the warnings. E2 is designed as a modular code and consists of a new event monitor module with an improved associator that allows for more rapid association with fewer triggers, while also adding several new alert filter checks that help minimize false alarms. Here, we outline the methodology and summarize the performance of this new online real-time system. The online performance from 2 October 2012 to 15 February 2013 shows, on average, ElarmS currently issues an alert 8: 68 +/- 3: 73 s after the first P-wave detection for all events across California. This time is reduced by 2 s in regions with dense station instrumentation. Standard deviations of magnitude, origin time are 0.4 magnitude units, 1.2 s, and the median location errors is 3.8 km. E2 successfully detected 26 of 29 earthquakes (M-ANSS > 3: 5) across California, while issuing two false alarms. E2 is now delivering alerts to ShakeAlert, which in turn distributes warnings to test users.
Full-text available
We propose a new algorithm to rapidly determine earthquake source and ground-motion parameters for earthquake early warning (EEW). This algorithm uses the acceleration, velocity, and displacement waveforms of a single three-component broadband (BB) or strong-motion (SM) sensor to perform real-time earthquake/noise discrimination and near/far source classification. When an earthquake is detected, the algorithm estimates the moment magnitude M, epicentral distance Δ, and peak ground velocity (PGV) at the site of observation. The algorithm was constructed by using an artificial neural network (ANN) approach. Our training and test datasets consist of 2431 three-component SM and BB records of 161 crustal earthquakes in California, Japan, and Taiwan with 3:1 ≤ M ≤ 7:6 at Δ≤ 115 km. First estimates be-come available at t 0 ˆ 0:25 s after the P pick and are regularly updated. We find that displacement and velocity waveforms are most relevant for the estimation of M and PGV, while acceleration is important for earthquake/noise discrimination. Including site corrections reduces the errors up to 10%. The estimates improve by an additional 10% if we use both the vertical and horizontal components of recorded ground motions. The uncertainties of the predicted parameters decrease with increasing time window length t 0 ; larger magnitude events show a slower decay of these uncertainties than small earthquakes. We compare our approach with the τ c algorithm and find that our prediction errors are around 60% smaller. However, in general there is a limitation to the prediction accuracy an EEW system can provide if based on single-sensor observations.
Nowadays natural disasters phenomena as hurricanes, volcanic eruptions, tsunamis or earthquakes, are still difficult to prevent. Based on signaling of the phenomenon appearance in the destructive area, important human losses and material damages are avoided. For that reason, WARNING turns into a key objective, both in theoretical and practical research. For the earthquakes, warning intervals are nevertheless very short — seconds to maximum one minute (Mexico City case). Even if the time window is reduced, automated decision measures are possible in case of a well organized system like important facilities. In Romania, the major seismic risk zone is located in Vrancea region. The earthquakes occurring in this area are the main sources for the seismic hazard on Romanian territory. Seismotectonic characteristics of the Vrancea region offers the opportunity to create and develop a rapid seismic warning system. This system is simple, reasonably low-priced, robust and allows warning in an approximately 25 seconds time window for Bucharest. Warning signal obtained is sent to the responsible factors and specific users in order to control automated blocking of the installations and to carry out the required protection actions.
The 11 March 2011 Tohoku-oki earthquake and tsunami that devastated coastal communities in three Japanese prefectures resulted in tremendous loss of life, loss of property, and community disruption. Yet research on the disaster pointed to differential impacts for people with disabilities compared to the rest of the population. Reconnaissance fieldwork took place in Miyagi and Iwate Prefectures 3, 10, and 17 months after the disaster. Interviews and observations point to situated access as a contributor to how and to what extent people with disabilities (PWD) received resources and services. That is, the ability of evacuees to acquire and utilize information, material resources, or services was based both on the physical location of the individual or group (including shelter type to where they evacuated) and the social standpoint or circumstances of the individual or group within that physical location. We offer a close examination of the effect of situational access for people with disabilities in particular. Where limitations were present, they often led to additional disparities.
This paper describes the use of Flex Hose for use by water and fire departments to address the Fire Following Earthquake issue. This paper starts with a history of the 1923 fire that destroyed part of the City of Berkeley. The paper describes how the water system infrastructure was insufficient to control this fire. This paper then discusses the pipe replacement and flex hose options that water utilities and fire departments can use to limit this kind of threat in modern cities for both urban-interface fires and fire following earthquake threats. For a comprehensive examination of Fire Following Earthquake and urban conflagration issues, see FFE (2004), a 350 page report edited by Charles Scawthorn, John Eidinger and Anshel Schiff.