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Benefits and Costs of Earthquake Early
Warning
by Jennifer A. Strauss and Richard M. Allen
ABSTRACT
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%.
INTRODUCTION
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 cost–benefit 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.
EARTHQUAKE EARLY WARNING
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
globally.
EEW AROUND THE WORLD
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 users—over 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 user’s 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 user’s 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 user’slo-
cation and counts down until the S-wave arrival (middle screen-
shot). By touching the “Map”link (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 Mexico’s 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 15–20 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 north–south 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 4–5sof
the origin time (Zschau et al., 2009). A regional EEW system is
undergoing testing in the Irpinia region east of Naples and
could provide 8–16 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.
HAZARD MITIGATION AND EEW
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 earthquake—those resulting from falling and flying
objects—and 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).
Hospitals
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
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 Iwate–Miyagi 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
disabled.
Elevators
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.
Manufacturing
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 9–12 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 controls—as 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 began—not
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
M≤3:6aftershocks, and produced only one false trigger (Ba-
kun et al., 1994).
COSTS AND BENEFITS
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 cost–ben-
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 $1.8–2.9 billion (in 2005 equivalent dollars), so
EEW could provide $1–1.5 billion in savings in a future similar
event.
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 injuries—is 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 FEMA’s cost–benefit 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.,
30–40 trains are moving at any given time, totaling 300–400
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
CONCLUSION
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.
DATA AND RESOURCES
The video of the early warning alert can be found at https://
www.youtube.com/watch?v=f3zGvs_hjdo (last accessed Feb-
ruary 2016). The semiconductor companies in California list-
ing can be found at http://semiconductorcompanies.com
(last accessed March 2015). Airbus A318 listing can be found
at http://www.airbus.com/presscentre/pressreleases/press-
release-detail/detail/new-airbus-aircraft-list-prices-for-2015/
(last accessed April 2015).
ACKNOWLEDGMENTS
ThisworkwasfundedbytheGordonandBettyMooreFoun-
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.
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Jennifer A. Strauss
Richard M. Allen
Berkeley Seismological Laboratory
University of California, Berkeley
215 McCone Hall, Number 4760
Berkeley, California 94720 U.S.A.
jastrauss@berkeley.edu
Published Online 23 March 2016
772 Seismological Research Letters Volume 87, Number 3 May/June 2016
