Jeffrey J. Love

United States Geological Survey, Denver, United States · Geomagnetism Program

Analysis is made of the geomagnetic-activity aa index covering solar cycle 11 to the beginning of 24, 1868-2011. Autocorrelation shows 27.0-d recurrent geomagnetic activity that is well-known to be prominent during solar-cycle minima; some minima also exhibit a smaller amount of 13.5-d recurrence. Previous work has shown that the recent solar minim...

A study is made of the relations between geomagnetic and geoelectric field variation, Earth‐surface impedance, and operational interference (“anomalies”) experienced on electric‐power systems across the contiguous United States during the 13–14 March, 1989, magnetic storm. For this, a 1‐min‐resolution sequence of geomagnetic field maps is construct...

An analysis is made of geophysical records of the 24 March 1940, magnetic storm and related reports of interference on long‐line communication and power systems across the contiguous United States and, to a lesser extent, Canada. Most long‐line system interference occurred during local daytime, after the second of two storm sudden commencements and...

A detailed analysis is made of horizontal‐component geomagnetic‐disturbance data acquired at the Colaba observatory in India recording the Carrington magnetic storm of September 1859. Prior to attaining its maximum absolute value, disturbance at Colaba increased with an e‐folding timescale of 0.46 hr (28 min). Following its maximum, absolute distur...

A study is made of the intensity of the Carrington magnetic storm of September 1859 as inferred from visual measurements of horizontal-component geomagnetic disturbance made at the Colaba observatory in India. Using data from modern observatories, a lognormal statistical model of storm intensity is developed, to characterize the maximum-negative va...

Presented is a list of voltages (electric potential differences) measured during magnetic storms on grounded long lines in the United States and Canada between 1891 and 1940. The sources for the list are published papers, technical documents, and newspapers. Each entry consists of the maximum voltage measured for each storm on a specified line conn...

Past studies found that large‐amplitude geomagnetically induced current (GIC) related to magnetospheric Ultra Low Frequency (ULF) waves tend to be associated with periods >120 s at magnetic latitudes >60°, with comparatively (a) smaller GIC amplitudes at lower latitudes and shorter wave periods and (b) fewer reports of waves associated with GIC at...

Anomaly lists are presented documenting operational interference to electricity power grids and communication networks in the United States and Canada during magnetic storms. Four of the anomaly lists apply for magnetic storms that occurred in March 1989, August 1972, March 1940, and for various storms 1946-2000; yet another list consists of statis...

An analysis is made of Earth‐surface geoelectric fields and voltages on electricity transmission power‐grids induced by a late‐phase E3 nuclear electromagnetic pulse (EMP). A hypothetical scenario is considered of an explosion of several hundred kilotons set several hundred kilometers above the eastern‐midcontinental United States. Ground‐level E3...

At present, the most reliable information for inferring storm‐time ground electric fields along electrical transmission lines comes from coarsely sampled, national‐scale magnetotelluric (MT) data sets, such as that provided by the EarthScope USArray program. An underlying assumption in the use of such data is that they adequately sample the spatial...

Past and possible future magnetic storm intensities are investigated. As part of this work, a dataset is developed of the most intense and second most intense storms for each of the past 11 solar cycles (1902–2016)—augmenting a traditional dataset that only covers the past 6 solar cycles (1957–2016) with recently published intensities for several m...

Previously, Tsurutani & Lakhina (2014) created estimates for a “perfect” interplanetary coronal mass ejection and performed simple calculations for the response of geospace, including urn:x-wiley:15427390:media:swe21087:swe21087-math-0001. In this study, these estimates are used to drive a coupled magnetohydrodynamic‐ring current‐ionosphere model o...

The 774 AD solar proton event (SPE) detected in cosmogenic nuclides had an inferred >1 GV (>430 MeV) fluence estimated to have been ∼30–70 times larger than that of the 1956 February 23 ground level event (GLE). The 1956 GLE was itself ∼2.5 times larger at >430 MeV than the episode of strong GLE activity from 1989 August–October. We use an inferred...

A once‐per‐century geoelectric hazard map is created for the U.S. high‐voltage power grid. A statistical extrapolation from 31 years of magnetic field measurements is made by identifying 84 geomagnetic storms with the Kp and Dst indices. Data from 24 geomagnetic observatories, 1,079 magnetotelluric survey sites, and 17,258 transmission lines are ut...

In support of projects for forecasting and mitigating the deleterious effects of extreme space weather storms, an examination is made of the intensities of magnetic superstorms recorded in the Dst index time series (1957–2016). Modified peak‐over‐threshold and solar cycle, block‐maximum samplings of the Dst time series are performed to obtain compi...

Geoelectric field time series can be estimated by convolving estimates of Earth‐surface impedance, such as those obtained from magnetotelluric survey measurements, with historical records of geomagnetic variation obtained at magnetic observatories. This straightforward procedure permits the mapping of geoelectric field variation during magnetic sto...

Analysis is made of low‐latitude ground‐based magnetometer data recording the magnetic superstorm of May 1921. By inference, the storm was driven by a series of interplanetary coronal mass ejections, one of which produced a maximum pressure on the magnetopause of ~64.5 nPa, sufficient to compress the subsolar magnetopause radius to ~5.3 Earth radii...

We evaluate worldwide low-latitude auroral activity associated with the great magnetic storm of September 1909 for which a minimum Dst value of −595 nT has recently been determined. From auroral observations, we calculate that the equatorward boundary of the auroral oval in the 1909 event was in the range from 31°–35° invariant latitude (assuming a...

Maps are presented of extreme-value geoelectric field amplitude and horizontal polarization for the Northeast United States. These maps are derived from geoelectric time series calculated for sites across the Northeast by frequency-domain multiplication (time-domain convolution) of 172 magnetotelluric impedance tensors, acquired during a survey, wi...

Analysis is made of solar observations and ground-based magnetometer data recording space weather before and during the magnetic superstorm of 25 September 1909. From these data, it is inferred that the storm was initiated by an interplanetary coronal-mass ejection having a mean Sun-to-Earth velocity of ~1,679 km/s. The commencement pressure on the...

Geomagnetic field data obtained through the INTERMAGNET program are convolved with with magnetotelluric surface impedance from four EarthScope USArray sites to estimate the geoelectric variations throughout the duration of a magnetic storm. A duration of time from June 22, 2016, to June 25, 2016, is considered which encompasses a magnetic storm of...

Tucked in a grove of thorny mesquite trees, on an ancient coral reef on the south side of the Hawaiian island of Oahu, west of Pearl Harbor, a small unmanned observatory quietly records the Earth’s time-varying magnetic field. The Honolulu Magnetic Observatory is 1 of 14 that the U.S. Geological Survey Geomag­netism Program operates at various loca...

Maps of extreme value, horizontal component geoelectric field amplitude are constructed for the Pacific Northwest United States (and parts of neighboring Canada). Multidecade long geoelectric field time series are calculated by convolving Earth surface impedance tensors from 71 discrete magnetotelluric survey sites across the region with historical...

A review is given of the present feasibility for accurately mapping geoelectric fields across North America in near-realtime by modeling geomagnetic monitoring and magnetotelluric survey data. Should this capability be successfully developed, it could inform utility companies of magnetic-storm interference on electric-power-grid systems. That real-...

Commonly, one-dimensional (1D) Earth impedances have been used to calculate the voltages induced across electric power transmission lines during geomagnetic storms under the assumption that much of the three-dimensional structure of the Earth gets smoothed when integrating along power transmission lines. We calculate the voltage across power transm...

In November 1882, an intense magnetic storm related to a large sunspot group caused widespread interference to telegraphs and telephone systems, and spectacular and unusual auroral displays. The (ring-current) storm-time disturbance index for this storm reached maximum -Dst ≈ 386 nT, comparable to Halloween storm of October 29-31, 2003, but from No...

Maps of extreme-value geoelectric field amplitude are constructed for the Mid-Atlantic United States, a region with high population density and critically important power-grid infrastructure. Geoelectric field time series for the years 1983-2014 are estimated by convolving Earth-surface impedances obtained from 61 magnetotelluric survey sites acros...

Maps of geoelectric amplitude covering about half the continental United States are presented that will be exceeded, on average, once per century in response to an extreme-intensity geomagnetic disturbance. These maps are constructed using an empirical parameterization of induction: convolving latitude-dependent statistical maps of extreme-value ge...

Despite its importance to a range of applied and fundamental studies, and obvious parallels to a robust network of magnetic-field observatories, long-term geoelectric field monitoring is rarely performed. The installation of a new geoelectric monitoring system at the Boulder magnetic observatory of the US Geological Survey is summarized. Data from...

An examination is made of opportunities and challenges for enhancing global, real-time geomagnetic monitoring that would be beneficial for a variety of operational projects. This enhancement in geomagnetic monitoring can be attained by expanding the geographic distribution of magnetometer stations, improving the quality of magnetometer data, increa...

This paper is the primary deliverable of the very first NASA Living With a Star Institute Working Group, Geomagnetically Induced Currents (GIC) Working Group. The paper provides a broad overview of the current status and future challenges pertaining to the science, engineering, and applications of the GIC problem. Science is understood here as the...

Geoelectric fields at the Earth's surface caused by magnetic storms constitute a hazard to the operation of electric-power grids and related infrastructure. The ability to estimate these geoelectric fields in close to real time and provide local predictions would better equip the industry to mitigate negative impacts on their operations. Here, we r...

Despite its importance to a range of applied and fundamental studies, and obvious parallels to a robust network of magnetic-field observatories, long-term geoelectric field monitoring is rarely carried out. The installation of a new geoelectric monitoring system at the Boulder Magnetic observatory of the U.S. Geological Survey is summarized. Data f...

On a sandy, arid plain, near the Rincon Moun­tain Visitor Center of Saguaro National Park, tucked in among brittlebush, creosote, and other hardy desert plants, is an unusual type of observatory—a small unmanned station that is used for monitor­ing the Earth’s variable magnetic field. Named for the nearby city of Tucson, Arizona, the observatory is...

In reaching across traditional disciplinary boundaries, solid-Earth geophysicists and space physicists are forging new collaborations to assess magnetic-storm hazards for electric-power grids. Future progress in evaluation storm-time geoelectric hazards will come primarily through monitoring, surveys, and modeling of related data.

Extreme space weather events are low-frequency, high-risk phenomena. Estimating their rates of occurrence, as well as their associated uncertainties, is difficult. In this study, we derive statistical estimates and uncertainties for the occurrence rate of an extreme geomagnetic storm on the scale of the Carrington event (or worse) occurring within...

Seventy-five years ago next week, a massive geomagnetic storm disrupted electrical power, interrupted radio broadcasts, and illuminated the night sky in a World War II battle theater.

In support of a multi-agency project for assessing induction hazards, we present maps of extreme-value geoelectric amplitudes over about half of the continental United States. These maps are constructed using a parameterization of induction: estimates of Earth-surface impedance, obtained at discrete geographic sites from magnetotelluric survey data...

Analysis is made of the long-term statistics of three different measures of ground level, storm time geomagnetic activity: instantaneous 1 min first differences in horizontal intensity ΔBh, the root-mean-square of 10 consecutive 1 min differences S, and the ramp change R over 10 min. Geomagnetic latitude maps of the cumulative exceedances of these...

Empirical impedance tensors obtained from EarthScope magnetotelluric data at sites distributed across the midwestern United States are used to examine the feasibility of mapping magnetic storm induction of geoelectric fields. With these tensors, in order to isolate the effects of Earth conductivity structure, we perform a synthetic analysis - calcu...

We report on the development and validation of an algorithm for estimating geoelectric fields induced in the lithosphere beneath an observatory during a magnetic storm. To accommodate induction in three-dimensional lithospheric electrical conductivity, we analyze a simple nine-parameter model: two horizontal layers, each with uniform electrical con...

Frederic Edwin Church's 1865 arctic landscape, Aurora Borealis, is a beautiful depiction of nature. It might also be a memorial reflection on the end of the war.

An examination is made of the hypothesis that the statistics of magnetic-storm-maximum intensities are the realization of a log-normal stochastic process. Weighted least-squares and maximum-likelihood methods are used to fit log-normal functions to −Dst storm-time maxima for years 1957-2012; bootstrap analysis is used to established confidence limi...

Magnetic storms are potentially hazardous to the activities and technological infrastructure of modern civilization. This reality was dramatically demonstrated during the great magnetic storm of March 1989, when surface geoelectric fields, produced by the interaction of the time-varying geomagnetic field with the Earth's electrically conducting int...

Several recently published reports have suggested that semi-stationary linear-cloud formations might be causally precursory to earthquakes. We examine the report of Guangmeng and Jie (2013), who claim to have predicted the 2012 M 6.0 earthquake in the Po Valley of northern Italy after seeing a satellite photograph (a digital image) showing a linear...

In support of projects for monitoring geomagnetic hazards for electric power grids, we develop a simple mathematical formalism, consistent with the time-causality of deterministic physics, for estimating electric fields that are induced in the Earth's lithosphere during magnetic storms. For an idealized model of the lithosphere, an infinite half-sp...

We review and analyse the phenomenon of time-invariant, periodic geomagnetic tides. These are generated by the deterministic physics of the ionospheric and oceanic dynamos, and, to a lesser extent, by the solar-quiet magnetosphere, and they are affected by currents induced in the Earth's electrically conducting interior. Using a long historical tim...

Since its formation in the late 1980s, the International Real-Time Magnetic Observatory Network (INTERMAGNET), a voluntary consortium of geophysical institutes from around the world, has promoted the operation of magnetic observatories according to modern standards [e.g., Rasson, 2007]. INTERMAGNET institutes have cooperatively developed infrastruc...

Schlumberger has introduced the geomagnetic referencing service (GRS) as a cost-effective alternative to conducting gyroscopic surveys in realtime drilling applications. GRS provides accurate data on wellbore position and enables timely corrections to wellbore trajectory. Surveying engineers use a proprietary algorithm, a 3D crustal model and a tim...

[1] We examine William Herschel's hypothesis that solar-cycle variation of the Sun's irradiance has a modulating effect on the Earth's climate and that this is, specifically, manifested as an anticorrelation between sunspot number and the market price of wheat. Since Herschel first proposed his hypothesis in 1801, it has been regarded with both int...

examine the claim that solar-terrestrial interaction, as measured by sunspots, solar wind velocity, and geomagnetic activity, might play a role in triggering earthquakes. We count the number of earthquakes having magnitudes that exceed chosen thresholds in calendar years, months, and days, and we order these counts by the corresponding rank of annu...

A magnetic observatory is a specially designed ground-based facility that supports time-series measurement of the Earth’s magnetic field. Observatory data record a superposition of time-dependent signals related to a fantastic diversity of physical processes in the Earth’s core, mantle, lithosphere, ocean, ionosphere, magnetosphere, and, even, the...

Jack Townshend, geophysicist and dedicated public servant, died on 13 August 2012 in Fairbanks, Alaska. He was 85. Jack's career with the federal government, most of it with the national magnetic observatory program, spanned more than six solar cycles of time, and he retired only days before his death. The duration of Jack's career encompassed an i...

Love and Gannon (2009) discovered that statistically, over a fifty year period the difference in the dawn and dusk disturbance-field H component at low latitudes (hourly averaged) is linearly proportional to Dst. If the difference is designated by δDD in units of nT/RE, then the Love-Gannon (L-G) relation is δDD = -0.2 Dst. At any time departures f...

We examine two stochastic models for consistency with observed long-term secular trends in sunspot number and a faint, but semi-persistent, 22-yr signal: (1) a null hypothesis, a simple one-parameter log-normal random-walk model of sunspot-number cycle-to-cycle change, and, (2) an alternative hypothesis, a two-parameter random-walk model with an im...

Statistical analysis is made of rare, extreme geophysical events recorded in historical data - counting the number of events k with sizes that exceed chosen thresholds during specific durations of time τ. Under transformations that stabilize data and model-parameter variances, the most likely Poisson-event occurrence rate, k/τ, applies for frequent...

1] Using Global Positioning System (GPS) data from sites near the 16 Oct. 1999 Hector Mine, California earthquake, Pulinets et al. (2007) identified anomalous changes in the ionospheric total electron content (TEC) starting one week prior to the earthquake. Pulinets (2007) suggested that precursory phenomena of this type could be useful for predict...

There is currently no reliable method for predicting earthquakes, although some claims of success have been published, and among these are reports of perturbations in the ionosphere prior to large earthquakes. In this presentation, we examine reports of precursors prior to two earthquakes: Hector Mine, CA 1999 and Tohoku, Japan 2011. Pulinets et al...

In this study, we test the accuracy of external magnetic field models using the USGS near real-time Dst and Kyoto Quicklook as a driver. The usefulness of these models as an operational tool has been limited by the lack of availability of a reliable real-time Dst index. It is difficult to prove the accuracy of any index due to its derived nature an...

Recent studies have led to speculation that solar-terrestrial interaction, measured by sunspot number and geomagnetic activity, has played an important role in global temperature change over the past century or so. We treat this possibility as an hypothesis for testing. We examine the statistical significance of cross-correlations between sunspot n...

Analysis is made of the geomagnetic-activity aa index and its source K-index data from groups of ground-based observatories in Britain, and Australia, 1868.0–2009.0, solar cycles 11–23. The K data show persistent biases, especially for high (low) K-activity levels at British (Australian) observatories. From examination of multiple subsets of the K...

Magnetic storms result from the dynamic interaction of the solar wind with the coupled magnetospheric-ionospheric system. Large storms represent a potential hazard for the activities and infrastructure of a modern, technologically based society [Baker et al., 2008]; they can cause the loss of radio communications, reduce the accuracy of global posi...

1] We study the seasonal variation of substorms, geomag-netic activity and their solar wind drivers in 1993–2008. The number of substorms and substorm mean duration depict an annual variation with maxima in Winter and Summer, respectively, reflecting the annual change of the local iono-sphere. In contradiction, substorm mean amplitude, substorm tot...

Analysis is made of K-index data from groups of ground-based geomagnetic observatories in Germany, Britain, and Australia, 1868.0–2009.0, solar cycles 11–23. Methods include nonparametric measures of trends and statistical significance used by the hydrological and climatological research communities. Among the three observatory groups, German K dat...

a b s t r a c t We produce a 1-min time resolution storm-time disturbance index, the USGS Dst, called Dst 8507-4SM . This index is based on minute resolution horizontal magnetic field intensity from low-latitude observatories in Honolulu, Kakioka, San Juan and Hermanus, for the years 1985–2007. The method used to produce the index uses a combinatio...

Geomagnetic-activity indices are among the longest directly-measured time series recording solar-terrestrial interaction. Derived from magnetometer data produced at mid-latitude ground-based observatories, the K index records the maximum variational range of magnetic-field disturbance over 3-hr durations of time at each individual observatory. The...

We present a low-latitude disturbance index with a one-minute time resolution, the USGS One-Minute Dst. Two versions of the index are produced - definitive and near-realtime - which utilize definitive and preliminary data, respectively, and data from the traditional 4 stations: Honolulu, San Juan, Kakioka, and Hermanus. A combination of time and fr...