Segall, P., A. L. Llenos, S.-H. Yun, A. M. Bradley, and E. M. Syracuse (2013), Time-dependent dike propagation from joint inversion of seismicity and deformation data, J. Geophys. Res. Solid Earth, 118, doi: 10.1002/2013JB010251.
Andrea Llenos
I am a research geophysicist whose research focuses on developing earthquake rate models for seismic hazard forecasts. I use statistical methods to characterize earthquake rate changes in catalogs, investigating the impacts these variations have on short-term earthquake forecasts as well as long-term seismic hazard models.
Biography
Education
PhD, 2010, Marine Geophysics, MIT/Woods Hole Oceanographic Institution Joint Program in Oceanography
ScB, 2004, Geology-Physics/Mathematics (with honors), Brown University, magna cum laude
ScB, 2004, Engineering (Mechanical), Brown University
Professional Experience
Research Geophysicist, US Geological Survey, Geologic Hazards Science Center, Golden, CO 2020-present
Research Geophysicist (term), US Geological Survey, Earthquake Science Center, Menlo Park/Moffett Field, CA 2015-2020
Mendenhall Postdoctoral Fellow, US Geological Survey, Earthquake Science Center, Menlo Park, CA 2011-2015
Postdoctoral Scholar, Stanford University, Stanford, CA 2010-2011
Graduate Research Assistant, Woods Hole Oceanographic Institution, Woods Hole, MA 2004-2010
Visiting Researcher, Institute of Statistical Mathematics, Tokyo, Japan 2008, 2009
Undergraduate Research Assistant, Dept. of Geo. Sci., Brown University, Providence, RI 2002-2004
NSF-REU Intern, University of Alaska Fairbanks, Geophysical Institute, Fairbanks, AK 2003
Undergraduate Research Assistant, Planetary Geosci., Brown University, Providence, RI 2001
Fellowships and Awards
Excellent Reviewer Award for Earth, Planets and Space 2019
Editors' Citation for Excellence in Refereeing for Geophysical Research Letters 2016
USGS Mendenhall Postdoctoral Fellowship 2011-2013
National Defense Science and Engineering Graduate Fellowship 2005-2008
Hollister Fellowship, Woods Hole Oceanographic Institution 2004-2005
Outstanding Student Award (in Mechanical Engineering) 2004
Undergraduate Research and Academics Award (in Geological Science) 2004
Science and Products
Date published: February 4, 2013
Status: Active Understanding Fluid Injection Induced Seismicity
Fluid injection induced seismicity has been reported since the 1960s. There are currently more than 150,000 injection wells associated with oil and gas production in 34 states in the conterminous US. Pore pressure disturbance caused by injection is generally considered the culprit for injection induced seismicity, but, not all injection causes seismicity. It is not well understood what...
Attribution: John Wesley Powell Center for Analysis and Synthesis
Year Published: 2020
Regionally Optimized Background Earthquake Rates from ETAS (ROBERE) for probabilistic seismic hazard assessment
We use an epidemic‐type aftershock sequence (ETAS) based approach to develop a regionally optimized background earthquake rates from ETAS (ROBERE) method for probabilistic seismic hazard assessment. ROBERE fits parameters to the full seismicity catalog for a region with maximum‐likelihood estimation, including uncertainty. It then averages the...
Llenos, Andrea L.; Michael, Andrew J.
Year Published: 2020
#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...
McBride, Sara; Llenos, Andrea L.; Page, Morgan T.; Van Der Elst, Nicholas
Year Published: 2019
Ensembles of ETAS models provide optimal operational earthquake forecasting during swarms: Insights from the 2015 San Ramon, California swarm
Earthquake swarms, typically modeled as time-varying changes in background seismicity that are driven by external processes such as fluid flow or aseismic creep, present challenges for operational earthquake forecasting. While the time decay of aftershock sequences can be estimated with the modified Omori law, it is difficult to forecast the...
Llenos, Andrea L.; Michael, Andrew J.
Year Published: 2019
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...
Llenos, Andrea L.; Van Der Elst, Nicholas
Year Published: 2018
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">M≥5...
Hardebeck, Jeanne L.; Llenos, Andrea L.; Michael, Andrew J.; Page, Morgan T.; Van Der Elst, Nicholas
Year Published: 2018
2018 one‐year seismic hazard forecast for the central and eastern United States from induced and natural earthquakes
This article describes the U.S. Geological Survey (USGS) 2018 one‐year probabilistic seismic hazard forecast for the central and eastern United States from induced and natural earthquakes. For consistency, the updated 2018 forecast is developed using the same probabilistic seismicity‐based methodology as applied in the two previous forecasts....
Petersen, Mark D.; Mueller, Charles; Moschetti, Morgan P.; Hoover, Susan M.; Rukstales, Kenneth S.; McNamara, Daniel E.; Williams, Robert A.; Shumway, Allison; Powers, Peter M.; Earle, Paul S.; Llenos, Andrea L.; Michael, Andrew J.; Rubinstein, Justin L.; Norbeck, Jack; Cochran, Elizabeth S.Attribution: Geologic Hazards Science Center, Natural Hazards, Earthquake Hazards Program, Region 7: Upper Colorado Basin
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Mark D. Petersen, Charles S. Mueller, Morgan P. Moschetti, Susan M. Hoover, Kenneth S. Rukstales, Daniel E. McNamara, Robert A. Williams, Allison M. Shumway, Peter M. Powers, Paul S. Earle, Andrea L. Llenos, Andrew J. Michael, Justin L. Rubinstein, Jack H. Norbeck, Elizabeth S. Cochran; 2018 One‐Year Seismic Hazard Forecast for the Central and Eastern United States from Induced and Natural Earthquakes. Seismological Research Letters ; 89 (3): 1049–1061. doi: https://doi.org/10.1785/0220180005
Year Published: 2017
Forecasting the (un)productivity of the 2014 M 6.0 South Napa aftershock sequence
The 24 August 2014 Mw 6.0 South Napa mainshock produced fewer aftershocks than expected for a California earthquake of its magnitude. In the first 4.5 days, only 59 M≥1.8 aftershocks occurred, the largest of which was an M 3.9 that happened a little over two days after the mainshock. We investigate the aftershock...
Llenos, Andrea L.; Michael, Andrew J.View Citation
Llenos, A. L., and A. J. Michael (2017), Forecasting the (un)productivity of the 2014 M 6.0 South Napa aftershock sequence, Seismol. Res. Lett., doi: 10.1785/0220170050.
Year Published: 2017
2017 One‐year seismic‐hazard forecast for the central and eastern United States from induced and natural earthquakes
We produce a one‐year 2017 seismic‐hazard forecast for the central and eastern United States from induced and natural earthquakes that updates the 2016 one‐year forecast; this map is intended to provide information to the public and to facilitate the development of induced seismicity forecasting models, methods, and data. The 2017 hazard model...
Petersen, Mark D.; Mueller, Charles; Moschetti, Morgan P.; Hoover, Susan M.; Shumway, Allison; McNamara, Daniel E.; Williams, Robert; Llenos, Andrea L.; Ellsworth, William L.; Rubinstein, Justin L.; McGarr, Arthur F.; Rukstales, Kenneth S.
Year Published: 2016
Seismic‐hazard forecast for 2016 including induced and natural earthquakes in the central and eastern United States
The U.S. Geological Survey (USGS) has produced a one‐year (2016) probabilistic seismic‐hazard assessment for the central and eastern United States (CEUS) that includes contributions from both induced and natural earthquakes that are constructed with probabilistic methods using alternative data and inputs. This hazard assessment builds on our 2016...
Petersen, Mark D.; Mueller, Charles; Moschetti, Morgan P.; Hoover, Susan M.; Llenos, Andrea L.; Ellsworth, William L.; Michael, Andrew J.; Rubinstein, Justin L.; McGarr, Arthur F.; Rukstales, Kenneth S.
Year Published: 2016
Characterizing potentially induced earthquake rate changes in the Brawley Seismic Zone, southern California
The Brawley seismic zone (BSZ), in the Salton trough of southern California, has a history of earthquake swarms and geothermal energy exploitation. Some earthquake rate changes may have been induced by fluid extraction and injection activity at local geothermal fields, particularly at the North Brawley Geothermal Field (NBGF) and at the Salton Sea...
Llenos, Andrea L.; Michael, Andrew J.View Citation
Llenos, A. L., and A. J. Michael (2016), Characterizing potentially induced earthquake rate changes in the Brawley Seismic Zone, southern California, Bull. Seismol. Soc. Am., 106, doi: 10.1785/0120150053.
Year Published: 2016
2016 one-year seismic hazard forecast for the Central and Eastern United States from induced and natural earthquakes
The U.S. Geological Survey (USGS) has produced a 1-year seismic hazard forecast for 2016 for the Central and Eastern United States (CEUS) that includes contributions from both induced and natural earthquakes. The model assumes that earthquake rates calculated from several different time windows will remain relatively stationary and can be used to...
Petersen, Mark D.; Mueller, Charles S.; Moschetti, Morgan P.; Hoover, Susan M.; Llenos, Andrea L.; Ellsworth, William L.; Michael, Andrew J.; Rubinstein, Justin L.; McGarr, Arthur F.; Rukstales, Kenneth S.Attribution: Geologic Hazards Science Center, Natural Hazards, Earthquake Hazards Program, Region 7: Upper Colorado Basin
View Citation
Petersen, M.D., Mueller, C.S., Moschetti, M.P., Hoover, S.M., Llenos, A.L., Ellsworth, W.L., Michael, A.J., Rubinstein, J.L., McGarr, A.F., and Rukstales, K.S., 2016, 2016 One-year seismic hazard forecast for the Central and Eastern United States from induced and natural earthquakes: U.S. Geological Survey Open-File Report 2016–1035, 52 p., http://dx.doi.org/10.3133/ofr20161035.
Year Published: 2015
Increasing seismicity in the U. S. midcontinent: Implications for earthquake hazard
Earthquake activity in parts of the central United States has increased dramatically in recent years. The space-time distribution of the increased seismicity, as well as numerous published case studies, indicates that the increase is of anthropogenic origin, principally driven by injection of wastewater coproduced with oil and gas from tight...
Ellsworth, William L.; Llenos, Andrea L.; McGarr, Arthur F.; Michael, Andrew J.; Rubinstein, Justin L.; Mueller, Charles S.; Petersen, Mark D.; Calais, EricView Citation
The Leading Edge > Volume 34, Issue 6 (June 2015) > 10.1190/tle34060618.1
Pre-USGS Publications
Llenos, A. L., and J. J. McGuire (2011), Detecting aseismic strain transients from seismicity data, J. Geophys. Res., 116, B06305, doi: 10.1029/2010JB007537.
Llenos, A. L., J. J. McGuire, and Y. Ogata (2009), Modeling seismic swarms triggered by aseismic transients, Earth Planet. Sci. Lett., 281, 59-69, doi:10.1016/j.epsl.2009.02.011.
Llenos, A. L., and J. J. McGuire (2007), Influence of fore-arc structure on the extent of great subduction zone earthquakes, J. Geophys. Res., 112, B09301, doi: 10.1029/2007JB004944.