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Nicholas van der Elst

Nicholas Van der Elst is a scientist in the Earthquake Hazards Program.

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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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Map showing aftershocks of 7.8 earthquake in Oaxaca, Mexico

The Past Holds the Key to the Future of Aftershock Forecasting

Release Date: MAY 7, 2018 The outcomes of past aftershock sequences can be used to describe the range of possibilities for a current sequence.
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Natural Hazards Mission Area, Earthquake Hazards Program
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The Past Holds the Key to the Future of Aftershock Forecasting

Release Date: MAY 7, 2018 The outcomes of past aftershock sequences can be used to describe the range of possibilities for a current sequence.
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...
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John Wesley Powell Center for Analysis and Synthesis
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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...
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Filter Total Items: 19

Fault roughness at seismogenic depths and links to earthquake behavior

Fault geometry affects the initiation, propagation, and cessation of earthquake rupture, as well as, potentially, the statistical behavior of earthquake sequences. We analyze 18,250 (−0.27 < M < 4.4) earthquakes of the 2016–2019 Cahuilla, California, swarm and, for the first time, use these high‐resolution earthquake locations to map, in detail, the roughness across an active fault surface at dept
Authors
Elizabeth S. Cochran, Morgan T. Page, Nicholas van der Elst, Zachary E. Ross, Daniel T. Trugman
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Aftershocks preferentially occur in previously active areas

The clearest statistical signal in aftershock locations is that most aftershocks occur close to their mainshocks. More precisely, aftershocks are triggered at distances following a power‐law decay in distance (Felzer and Brodsky, 2006). This distance decay kernel is used in epidemic‐type aftershock sequence (ETAS) modeling and is typically assumed to be isotropic, even though individual sequences
Authors
Morgan T. Page, Nicholas van der Elst
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake 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
Authors
Nicholas van der Elst, Jeanne L. Hardebeck, Andrew J. Michael, Sara McBride, Elizabeth Vanacore
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Improvements to the Third Uniform California Earthquake Rupture Forecast ETAS Model (UCERF3‐ETAS)

We describe recent improvements to the Third Uniform California Earthquake Rupture Forecast ETAS Model (UCERF3‐ETAS), which continues to represent our most advanced and complete earthquake forecast in terms of relaxing segmentation assumptions and representing multifault ruptures, elastic‐rebound effects, and spatiotemporal clustering (the latter to represent aftershocks and otherwise triggered ev
Authors
Edward H. Field, Kevin R. Milner, Morgan T. Page, William H. Savran, Nicholas van der Elst
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center, Geologic Hazards Science Center

B-positive: A robust estimator of aftershock magnitude distribution in transiently incomplete catalogs

The earthquake magnitude-frequency distribution is characterized by the b-value, which describes the relative frequency of large versus small earthquakes. It has been suggested that changes in b-value after an earthquake can be used to discriminate whether that earthquake is part of a foreshock sequence or a more typical mainshock-aftershock sequence, with a decrease in b-value heralding a larger
Authors
Nicholas van der Elst
By
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
Authors
Nicholas van der Elst, Jeanne L. Hardebeck, Andrew J. Michael
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

The U.S. Geological Survey’s Rapid Seismic Array Deployment for the 2019 Ridgecrest Earthquake Sequence

Rapid seismic deployments following large earthquakes capture ephemeral near‐field recordings of aftershocks and ambient noise that can provide valuable data for seismological studies. The U.S. Geological Survey installed 19 temporary seismic stations following the 4 July 2019 Mw 6.4 and 6 July 2019 (UTC) Mw 7.1 earthquakes near the city of Ridgecrest, California. The stations record the aftershoc
Authors
Elizabeth S. Cochran, Emily Wolin, Daniel E. McNamara, Alan Yong, David C. Wilson, Mark Alvarez, Nicholas van der Elst, Adria Ruth McClain, Jamison Haase Steidl
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

#EarthquakeAdvisory: Exploring discourse between government officials, news media and social media during the Bombay Beach 2016 Swarm

Communicating probabilities of natural hazards to varied audiences is a notoriously difficult task. Many of these challenges were encountered during the 2016 Bombay Beach, California, swarm of ~100 2≤M≤4.3 earthquakes, which began on 26 September 2016 and lasted for several days. The swarm’s proximity to the southern end of the San Andreas fault caused concern that a larger earthquake could be tri
Authors
Sara McBride, Andrea L. Llenos, Morgan T. Page, Nicholas van der Elst
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Improving earthquake forecasts during swarms with a duration model

Earthquake swarms present a challenge for operational earthquake forecasting because they are driven primarily by transient external processes, such as fluid flow, the behavior and duration of which are difficult to predict. In this study, we develop a swarm duration model to estimate how long a swarm is likely to last based on actuarial statistics of previous swarms in a given region. We demonstr
Authors
Andrea L. Llenos, Nicholas van der Elst
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Developing earthquake forecast templates for fast and effective communication

No abstract available.
Authors
Sara McBride, Andrew J. Michael, Anne M. Wein, Jeanne L. Hardebeck, Julia S. Becker, Sally H. Potter, Suzanne C. Perry, Morgan T. Page, Matthew Gerstenberger, Edward H. Field, Nicholas van der Elst
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Western Geographic Science Center

Updated California aftershock parameters

Reasenberg and Jones (1989) introduced a statistical model for aftershock rate following a mainshock along with estimates of “generic” California parameter values based on past aftershock sequences. The Reasenberg and Jones (1989) model has been used for decades to issue aftershock forecasts following M≥5 mainshocks in California. Here, we update the “generic” parameters for California through a f
Authors
Jeanne L. Hardebeck, Andrea L. Llenos, Andrew J. Michael, Morgan T. Page, Nicholas van der Elst
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Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Turing-style tests for UCERF3 synthetic catalogs

Epidemic-Type Aftershock Sequence (ETAS) catalogs generated from the 3rd Uniform California Earthquake Rupture Forecast (UCERF3) model are unique in that they are the first to combine a complex, fault-based long-term forecast with short-term earthquake clustering statistics. We present Turing-style tests to examine whether these synthetic catalogs can successfully imitate observed earthquake behav
Authors
Morgan T. Page, Nicholas van der Elst
By
Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

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