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Jeanne Hardebeck

Jeanne Hardebeck is a research scientist in the Earthquake Science Center.

Research Interests

- Crustal stress and the strength of faults.

- Earthquake statistics and testing earthquake forecasting methods.

- California stress field and seismotectonics.

- Earthquake triggering and effects on probabilistic seismic hazard assessment.

Professional Experience

  • Research Geophysicist, USGS Earthquake Hazards Team, 2004-present

  • Mendenhall Postdoctoral Scholar, USGS Earthquake Hazards Team, 2003-2004

  • Green Postdoctoral Scholar, Scripps Institution of Oceanography, U.C. San Diego, 2000-2003

  • Graduate Research Assistant, California Institute of Technology, 1994-2000

Education and Certifications

  • Ph.D. Geophysics, California Institute of Technology, 2001

  • M.S. Geophysics, California Institute of Technology, 1997

  • A.B. Computer Science, Cornell University, 1993

Honors and Awards

  • Presidential Early Career Award for Scientists and Engineers (PECASE), 2009

  • James B. Macelwane Medal, American Geophysical Union, 2007

  • Charles F. Richter Early Career Award, Seismological Society of America, 2006

Science and Products

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Map showing regional faults and Coso field near Ridgecrest

Could the M7.1 Ridgecrest, CA Earthquake Sequence Trigger a Large Earthquake Nearby?

Release Date: SEPTEMBER 30, 2019 Two of the first questions that come to mind for anyone who just felt an earthquake are, “Will there be another one?” and “Will it be larger?”.
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center, Geologic Hazards Science Center
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Could the M7.1 Ridgecrest, CA Earthquake Sequence Trigger a Large Earthquake Nearby?

Release Date: SEPTEMBER 30, 2019 Two of the first questions that come to mind for anyone who just felt an earthquake are, “Will there be another one?” and “Will it be larger?”.
Learn More
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USGS science for a changing world logo

Operational Earthquake Forecasting – Implementing a Real-Time System for California

It is well know that every earthquake can spawn others (e.g., as aftershocks), and that such triggered events can be large and damaging, as recently demonstrated by L’Aquila, Italy and Christchurch, New Zealand earthquakes. In spite of being an explicit USGS strategic-action priority (http://pubs.usgs.gov/of/2012/1088; page 32), the USGS currently lacks an automated system with which to forecast s...
By
John Wesley Powell Center for Analysis and Synthesis
link

Operational Earthquake Forecasting – Implementing a Real-Time System for California

It is well know that every earthquake can spawn others (e.g., as aftershocks), and that such triggered events can be large and damaging, as recently demonstrated by L’Aquila, Italy and Christchurch, New Zealand earthquakes. In spite of being an explicit USGS strategic-action priority (http://pubs.usgs.gov/of/2012/1088; page 32), the USGS currently lacks an automated system with which to forecast s...
Learn More

High resolution earthquake relocations and focal mechanisms with preferred fault planes for the 2020 Maacama sequence

This page contains results from analysis of 2020 Maacama earthquake sequence, including the detected and relocated earthquake catalog along with associated focal mechanisms and preferred fault planes as derived in: Shelly, D. R., R. J. Skoumal, and J. L. Hardebeck, Fracture-mesh faulting in the swarm-like 2020 Maacama sequence revealed by high-precision earthquake detection, location, and focal m
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Geologic Hazards Science Center
Filter Total Items: 51

Using corrected and imputed polarity measurements to improve focal mechanisms in a regional earthquake catalog near the Mt. Lewis Fault Zone, California

We utilized relative polarity measurements and machine learning techniques to better resolve focal mechanisms and stress orientations considering a catalog of ∼29,000 relocated earthquakes that occurred during 1984–2021 in the southeastern San Francisco Bay Area. Earthquake focal mechanisms are commonly produced using P wave first motion polarities, which traditionally requires events to be well-r
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Physical properties of the crust influence aftershock locations

Aftershocks do not uniformly surround a mainshock, and instead occur in spatial clusters. Spatially variable physical properties of the crust may influence the spatial distribution of aftershocks. I study four aftershock sequences in Southern California (1992 Landers, 1999 Hector Mine, 2010 El Mayor—Cucapah, and 2019 Ridgecrest) to investigate which physical properties are spatially correlated wit
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Earthquakes in the shadows: Why aftershocks occur at surprising locations

For decades there has been a debate about the relative effects of dynamic versus static stress triggering of aftershocks. According to the static Coulomb stress change hypothesis, aftershocks should not occur in stress shadows—regions where static Coulomb stress has been reduced. We show that static stress shadows substantially influence aftershock occurrence following three M ≥ 7 California mains
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Using machine learning techniques with incomplete polarity datasets to improve earthquake focal mechanism determination

Earthquake focal mechanisms are traditionally produced using P‐wave first‐motion polarities and commonly require well‐recorded seismicity. A recent approach that is less dependent on high signal‐to‐noise exploits similar waveforms to produce relative polarity measurements between earthquake pairs. Utilizing these relative polarity measurements, it is possible to produce composite focal mechanisms
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Natural Hazards Mission Area, Earthquake Hazards Program, Volcano Hazards Program, Earthquake Science Center, Volcano Science Center

Prospective and retrospective evaluation of the U.S. Geological Survey public aftershock forecast for the 2019-2021 Southwest Puerto Rico Earthquake and aftershocks

The Mw 6.4 Southwest Puerto Rico Earthquake of 7 January 2020 was accompanied by a robust fore‐ and aftershock sequence. The U.S. Geological Survey (USGS) has issued regular aftershock forecasts for more than a year since the mainshock, available on a public webpage. Forecasts were accompanied by interpretive and informational material, published in English and Spanish. Informational products incl
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Does earthquake stress drop increase with depth in the crust?

We combine earthquake spectra from multiple studies to investigate whether the increase in stress drop with depth often observed in the crust is real, or an artifact of decreasing attenuation (increasing Q) with depth. In many studies, empirical path and attenuation corrections are assumed to be independent of the earthquake source depth. We test this assumption by investigating whether a realisti
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

A unified model of crustal stress heterogeneity from borehole breakouts and earthquake focal mechanisms

Observations of crustal stress orientation from the regional inversion of earthquake focal mechanisms often conflict with those from borehole breakouts, possibly indicating local stress heterogeneity, either laterally or with depth. To investigate this heterogeneity, we compiled SHmax estimates from previous studies for 57 near‐vertical boreholes with measured breakout azimuths across the Los Ange
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Spatial clustering of aftershocks impacts the performance of physics‐based earthquake forecasting models

I explore why physics‐based models of earthquake triggering rarely outperform statistical models in prospective testing, outside of limited spatial‐temporal windows. Pseudo‐prospective tests on suites of synthetic aftershock sequences show that a major factor is the level of unmodeled spatial clustering of the direct aftershocks triggered by the mainshock. The synthetic sequences are generated fro
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

A stress-similarity triggering model for aftershocks of the MW6.4 and MW7.1 Ridgecrest earthquakes

The July 2019 Mw 6.4 and 7.1 Ridgecrest earthquakes triggered numerous aftershocks, including clusters of off‐fault aftershocks in an extensional stepover of the Garlock fault, near the town of Olancha, and near Panamint Valley. The locations of the off‐fault aftershocks are consistent with the stress‐similarity model of triggering, which hypothesizes that aftershocks preferentially occur in areas
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Are the stress drops of small earthquakes good predictors of the stress drops of moderate-to-large earthquakes?

The stress drops of small earthquakes often exhibit spatial patterns of variability. If moderate and large earthquakes follow the same spatial patterns, the stress drops of possible future damaging earthquakes could be better predicted by considering the stress drops of nearby small events. Better stress drop predictability could reduce ground-motion uncertainty in Probabilistic Seismic Hazard As
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Localized fluid discharge by tensile cracking during the post-seismic period in subduction zones

It is thought that extensional structures (extensional cracks and normal faults) generated during the post-seismic period create fluid pathways that enhance the drainage of the subducting plate interface, thus reducing the pore pressure and increasing fault strength. However, it remains to be elucidated how much pore fluid pressure decreases by the extension crack formation. Here we examined i) th
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Potential duration of aftershocks of the 2020 southwestern Puerto Rico earthquake

AbstractAftershocks (earthquakes clustered spatially and chronologically near the occurrence of a causative earthquake) are ongoing in southwestern Puerto Rico after a series of earthquakes, which include a magnitude 6.4 earthquake that occurred near Barrio Indios, Guayanilla, on January 7, 2020, and affected the surrounding area. This report estimates the expected duration of these aftershocks by
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

SATSI

SATSI (Spatial And Temporal Stress Inversion) is a modified version of Michael's (JGR 1984, 1987) code that inverts focal mechanism data for a spatially and/or temporally varying stress field.

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Earthquake Hazards Program

HASH 1.2

HASH is a Fortran 77 code that computes double-couple earthquake focal mechanisms from P-wave first motion polarity observations, and optionally S/P amplitude ratios.

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Earthquake Hazards Program

Science and Products