Erin Wirth Moriarty
Professional name: Erin A. Wirth
My research focuses on earthquake hazards, specifically in subduction zone settings. I am currently using 3-D numerical simulations to predict earthquake ground motions associated with large earthquakes in the Cascadia subduction zone, as well as on crustal faults systems. I integrate my work with geologic and geophysical observations from previous earthquakes, and work closely with engineers and social scientists to improve earthquake resilience in the Pacific Northwest. I am also interested in the generation of strong ground motions by distinct patches on the megathrust (i.e., as observed in the 2011 M9.0 Tohoku, Japan earthquake) and the amplification of ground motions by deep sedimentary basins (e.g., the Seattle basin).
My other research interests focus on using seismic observations and numerical modeling to characterize the structure and dynamics of Earth’s interior. Previously, I have used seismological techniques (such as receiver functions and shear wave splitting) to interrogate deformational processes and the extent of hydration in subduction systems worldwide.
Education
2014 Ph.D. Geology & Geophysics, Yale University
2011 M.Phil. Geology & Geophysics, Yale University
2009 B.S. Physics, New York University
Appointments
2017-Present Research Geophysicist, U.S. Geological Survey, Seattle, WA
2017-Present Affiliate Assistant Professor, University of Washington
2014-2018 Duty Seismologist, Pacific Northwest Seismic Network, University of Washington
2014-2017 Postdoctoral Research Associate, Department of Earth & Space Sciences, University of Washington
2009-2014 Graduate Student Researcher, Department of Geology & Geophysics, Yale University
Science and Products
Filter Total Items: 19
Impact of down-dip rupture limit and high stress drop subevents on coseismic land-level change during Cascadia megathrust earthquakes
Seismic hazard associated with Cascadia megathrust earthquakes is strongly dependent on the landward rupture extent and heterogeneous fault properties. We use 3-D numerical simulations and a seismic velocity model for Cascadia to estimate coseismic deformation due to ~M9 earthquake scenarios. Our earthquake source model is based on observations of the 2010 M8.8 Maule and 2011 M9.0 Tohoku earthquak
Authors
Erin A. Wirth, Arthur Frankel
SKS splitting beneath Mount St. Helens: Constraints on subslab mantle entrainment
Observations of seismic anisotropy can provide direct constraints on the character of mantle flow in subduction zones, critical for our broader understanding of subduction dynamics. Here we present over 750 new SKS splitting measurements in the vicinity of Mount St. Helens in the Cascadia subduction zone using a combination of stations from the iMUSH broadband array and Cascades Volcano Observator
Authors
Caroline M Eakin, Erin A. Wirth, Abraham Wallace, Carl W Ulberg, Kenneth C Creager, Geoffrey A Abers
Source-dependent amplification of earthquake ground motions in deep sedimentary basins
Deep sedimentary basins amplify long-period shaking from seismic waves, increasing the seismic hazard for cities within such basins. We perform 3-D simulations of point source earthquakes distributed around the Seattle and Tacoma basins in Washington State, to examine the dependence of basin amplification on source azimuth, depth, and earthquake type. For periods between 1-10 s, the pattern of amp
Authors
Erin Wirth, John E. Vidale, Arthur Frankel, Thomas L. Pratt
2018 report on incorporating sedimentary basin response into the design of tall buildings in Seattle, Washington
On March 22, 2018, the Seattle Department of Construction and Inspections (SDCI) and the U.S. Geological Survey (USGS) convened a workshop of engineers and seismologists to provide guidance on incorporating sedimentary basin response into the design of tall buildings in Seattle. This workshop provided recommendations that build on those from a March 2013 workshop (Chang and others, 2014), primaril
Authors
Erin A. Wirth, Susan W. Chang, Arthur Frankel
Broadband synthetic seismograms for magnitude 9 earthquakes on the Cascadia Megathrust based on 3D simulations and stochastic synthetics, Part 2: Rupture parameters and variability
We used a combination of 3D finite‐difference simulations (<1 Hz) and 1D stochastic synthetics (>1 Hz) to generate broadband (0–10 Hz) synthetic seismograms for numerous Mw 9 earthquake rupture scenarios on the Cascadia megathrust. Slip consists of multiple high‐stress‐drop subevents (Mw 8) with short rise times on the deeper portions of the fault, superimposed on a background slip distribution
Authors
Erin A. Wirth, Arthur Frankel, Nasser A. Marafi, John E. Vidale, William J. Stephenson
Evaluating a kinematic method for generating broadband ground motions for great subduction zone earthquakes: Application to the 2003 Mw 8.3 Tokachi‐Oki earthquake
We compare broadband synthetic seismograms with recordings of the 2003 MwMw 8.3 Tokachi‐Oki earthquake to evaluate a compound rupture model, in which slip on the fault consists of multiple high‐stress‐drop asperities superimposed on a background slip distribution with longer rise times. Low‐frequency synthetics (<1 Hz<1 Hz) are calculated using deterministic, 3D finite‐difference simulations and
Authors
Erin A. Wirth, Arthur Frankel, John E. Vidale
Effects of deep basins on structural collapse during large subduction earthquakes
Deep sedimentary basins are known to increase the intensity of ground motions, but this effect is implicitly considered in seismic hazard maps used in U.S. building codes. The basin amplification of ground motions from subduction earthquakes is particularly important in the Pacific Northwest, where the hazard at long periods is dominated by such earthquakes. This paper evaluates the effects of bas
Authors
Nasser A. Marafi, Marc O. Eberhard, Jeffrey W. Berman, Erin A. Wirth, Arthur Frankel
Science and Products
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- Publications
Filter Total Items: 19
Impact of down-dip rupture limit and high stress drop subevents on coseismic land-level change during Cascadia megathrust earthquakes
Seismic hazard associated with Cascadia megathrust earthquakes is strongly dependent on the landward rupture extent and heterogeneous fault properties. We use 3-D numerical simulations and a seismic velocity model for Cascadia to estimate coseismic deformation due to ~M9 earthquake scenarios. Our earthquake source model is based on observations of the 2010 M8.8 Maule and 2011 M9.0 Tohoku earthquakAuthorsErin A. Wirth, Arthur FrankelSKS splitting beneath Mount St. Helens: Constraints on subslab mantle entrainment
Observations of seismic anisotropy can provide direct constraints on the character of mantle flow in subduction zones, critical for our broader understanding of subduction dynamics. Here we present over 750 new SKS splitting measurements in the vicinity of Mount St. Helens in the Cascadia subduction zone using a combination of stations from the iMUSH broadband array and Cascades Volcano ObservatorAuthorsCaroline M Eakin, Erin A. Wirth, Abraham Wallace, Carl W Ulberg, Kenneth C Creager, Geoffrey A AbersSource-dependent amplification of earthquake ground motions in deep sedimentary basins
Deep sedimentary basins amplify long-period shaking from seismic waves, increasing the seismic hazard for cities within such basins. We perform 3-D simulations of point source earthquakes distributed around the Seattle and Tacoma basins in Washington State, to examine the dependence of basin amplification on source azimuth, depth, and earthquake type. For periods between 1-10 s, the pattern of ampAuthorsErin Wirth, John E. Vidale, Arthur Frankel, Thomas L. Pratt2018 report on incorporating sedimentary basin response into the design of tall buildings in Seattle, Washington
On March 22, 2018, the Seattle Department of Construction and Inspections (SDCI) and the U.S. Geological Survey (USGS) convened a workshop of engineers and seismologists to provide guidance on incorporating sedimentary basin response into the design of tall buildings in Seattle. This workshop provided recommendations that build on those from a March 2013 workshop (Chang and others, 2014), primarilAuthorsErin A. Wirth, Susan W. Chang, Arthur FrankelBroadband synthetic seismograms for magnitude 9 earthquakes on the Cascadia Megathrust based on 3D simulations and stochastic synthetics, Part 2: Rupture parameters and variability
We used a combination of 3D finite‐difference simulations (<1 Hz) and 1D stochastic synthetics (>1 Hz) to generate broadband (0–10 Hz) synthetic seismograms for numerous Mw 9 earthquake rupture scenarios on the Cascadia megathrust. Slip consists of multiple high‐stress‐drop subevents (Mw 8) with short rise times on the deeper portions of the fault, superimposed on a background slip distributionAuthorsErin A. Wirth, Arthur Frankel, Nasser A. Marafi, John E. Vidale, William J. StephensonEvaluating a kinematic method for generating broadband ground motions for great subduction zone earthquakes: Application to the 2003 Mw 8.3 Tokachi‐Oki earthquake
We compare broadband synthetic seismograms with recordings of the 2003 MwMw 8.3 Tokachi‐Oki earthquake to evaluate a compound rupture model, in which slip on the fault consists of multiple high‐stress‐drop asperities superimposed on a background slip distribution with longer rise times. Low‐frequency synthetics (<1 Hz<1 Hz) are calculated using deterministic, 3D finite‐difference simulations andAuthorsErin A. Wirth, Arthur Frankel, John E. VidaleEffects of deep basins on structural collapse during large subduction earthquakes
Deep sedimentary basins are known to increase the intensity of ground motions, but this effect is implicitly considered in seismic hazard maps used in U.S. building codes. The basin amplification of ground motions from subduction earthquakes is particularly important in the Pacific Northwest, where the hazard at long periods is dominated by such earthquakes. This paper evaluates the effects of basAuthorsNasser A. Marafi, Marc O. Eberhard, Jeffrey W. Berman, Erin A. Wirth, Arthur Frankel - News