A5086788837- earthquake and tectonic studies
- Seismic Waves and Analysis
- Seismic Performance and Analysis
- Seismology and Earthquake Studies
- Seismic Imaging and Inversion Techniques
- High-pressure geophysics and materials
- Landslides and related hazards
- Earthquake Detection and Analysis
- Geological Modeling and Analysis
- Geological and Geochemical Analysis
- Structural Health Monitoring Techniques
- Geophysics and Sensor Technology
- Wind and Air Flow Studies
- Geological and Tectonic Studies in Latin America
- Geotechnical Engineering and Soil Mechanics
- Geological and Geophysical Studies Worldwide
- Geotechnical Engineering and Underground Structures
- Methane Hydrates and Related Phenomena
- Tropical and Extratropical Cyclones Research
- Geotechnical and Geomechanical Engineering
- Structural Response to Dynamic Loads
- Atmospheric and Environmental Gas Dynamics
- Reservoir Engineering and Simulation Methods
- Geographic Information Systems Studies
- Risk and Safety Analysis
United States Geological Survey
2014-2024
Earthquake Science Center
2015-2023
University of Washington
2011-2022
Earth and Space Research
2015-2018
Denver Federal Center
1994-2010
California Geological Survey
2004-2008
University of Alaska Fairbanks
2003
Central Washington University
2003
Alaska Department of Natural Resources
2003
Alaska Division of Geological and Geophysical Surveys
2003
Research Article| July 01, 1995 Mapping Seismic Hazard in the Central and Eastern United States Arthur Frankel U.S. Geological Survey MS 966, Box 25046 Denver Federal Center Denver, CO 80225 (A. F.) Search for other works by this author on: GSW Google Scholar Seismological Letters (1995) 66 (4): 8–21. https://doi.org/10.1785/gssrl.66.4.8 Article history first online: 09 Mar 2017 Cite View This Citation Add to Manager Share Icon Twitter LinkedIn Tools Get Permissions Site Frankel; States....
Synthetic seismograms produced by the finite difference method are used to study scattering of elastic and acoustic waves in two‐dimensional media with random spatial variations seismic velocity. The results this provide important insights about propagation short‐period (< 1 s) earth's crust place significant constraints on fluctuation spectrum crustal heterogeneity length scales from tens kilometers meters. synthetic analyzed determine variation travel times waveforms across arrays...
First posted April 1, 2008 Revised May 3, For additional information, contact: Natural HazardsU.S. Geological Survey12201 Sunrise Valley DriveReston, VA 20192 The U.S. Survey (USGS) National Seismic Hazard Maps display earthquake ground motions for various probability levels across the United States and are applied in seismic provisions of building codes, insurance rate structures, risk assessments, other public policy. This update maps incorporates new findings on shaking, faults,...
In this release of hazard maps we present numerous and data with varying parameters. The computations for these used 50 year return periods on firm rock at 760 m/sec. All the were prepared by combining derived from spatially- smoothed historic seismicity fault-specific sources. For more information please read our full documentation. Although have been U.S. Geological Survey, no warranty, expressed or implied is made USGS as to accuracy related material nor shall fact distribution constitute...
The MW (moment magnitude) 7.9 Denali fault earthquake on 3 November 2002 was associated with 340 kilometers of surface rupture and the largest strike-slip in North America almost 150 years. It illuminates mechanics hazards large faults. began thrusting previously unrecognized Susitna Glacier fault, continued right-slip then took a right step Totschunda fault. There is good correlation between geologically observed geophysically inferred moment release. produced unusually strong distal...
The national seismic hazard maps for the conterminous United States have been updated to account new methods, models, and data that obtained since 2008 were released (Petersen others, 2008). input models are improved from those implemented in by using ground motion incorporated about twice as many earthquake strong shaking incorporating additional scientific studies indicate broader ranges of source models. These time-independent shown 2-percent 10-percent probability exceedance 50 years...
Abstract A new model of seismic coda is presented, based on the balance between energy scattered from direct wave and in coda. This energy-flux results a simple formula for amplitude time decay that explicitly differentiates scattering intrinsic (anelastic) attenuation medium. valid both weak strong implicitly includes multiple scattering. The tested using synthetic seismograms produced finite difference simulations propagation through media with random spatial variations velocity. Some also...
During 2017–2018, the National Seismic Hazard Model for conterminous United States was updated as follows: (1) an seismicity catalog incorporated, which includes new earthquakes that occurred from 2013 to 2017; (2) in central and eastern (CEUS), ground motion models were incorporate median estimates, modified assessments of associated epistemic uncertainties aleatory variabilities, soil amplification factors; (3) western (WUS), amplified shaking estimates long-period motions at sites...
The US National Seismic Hazard Model (NSHM) was updated in 2023 for all 50 states using new science on seismicity, fault ruptures, ground motions, and probabilistic techniques to produce a standard of practice public policy other engineering applications (defined return periods greater than ∼475 or less ∼10,000 years). Changes time-independent seismic hazard (both increases decreases compared previous NSHMs) are substantial because the model considers more data earthquake rupture forecasts...
Abstract The finite-difference method is used to propagate elastic waves through a 3-D model of the Santa Clara Valley, an alluvium-filled basin that underlies city San Jose, California. was based on depth bedrock information from water wells in area. simulation corresponded region 30 (east-west) by 22 (north-south) 6 (depth) km and contained about 4 million grid points. Synthetic seismograms are accurate at frequencies up 1 Hz. Motions magnitude 4.4 aftershock Loma Prieta earthquake were...
Abstract This article compares techniques for calculating broadband time histories of ground motion in the near field a finite fault by comparing synthetics with strong-motion data set 1994 Northridge earthquake. Based on this comparison, preferred methodology is presented. Ground-motion-simulation are divided into two general methods: kinematic- and composite-fault models. Green's functions three types evaluated: stochastic, empirical, theoretical. A hybrid scheme found to give best fit...
Abstract Three-dimensional finite difference simulations of elastic waves in the San Bernardino Valley were performed for two hypothetical earthquakes on Andreas fault: a point source with moment magnitude M5 and an extended rupture M6.5. A method is presented incorporating arbitrary focal mechanism grid. Synthetics from 3-D are compared those derived 2-D (vertical cross section) 1-D (flat-layered) models. The synthetic seismograms exhibit large surface produced by conversion incident S at...
We compare the attenuation of high‐frequency (3–30 Hz) shear waves for crustal paths in New York State, South Africa, and southern California over source‐receiver distances about 10–400 km. The data consist digital recordings S (Δ = 5–100 km) Lg 100–400 produced by earthquakes. use a coda normalization method to remove effects site amplification source excitation from amplitudes waves. Over entire distance range studied (10–400 km), amplitude decay 3‐Hz wave energy is considerably less...
The high‐frequency falloff ω −γ of earthquake displacement spectra and the b value aftershock sequences are attributed to character spatially varying strength along fault zones. I assume that high frequency energy a main shock is produced by self‐similar distribution subevents, where number subevents with radii greater than R proportional −D , D being fractal dimension. In this model, an composed hierarchical set smaller earthquakes. static stress drop parameterized be η assumed drop. find =...
Using small events as empirical Green functions, which include path, site, and instrument effects on the P waveforms, source parameters were estimated for 25 ML 3.4 to 4.4 associated with 1986 North Palm Springs earthquake. The static stress drops ranged from 3 80 bars, moments of 0.7 11 × 1021 dyne-cm. There was a spatial pattern aftershocks showed increasing values along fault plane toward northwest compared relatively low near hypocenter mainshock. highest outside main area slip, are...
New seismic hazard maps have been developed for the conterminous United States using latest data, models, and methods available assessing earthquake hazard. The models incorporate new information on rupture behavior observed in recent earthquakes; fault studies that use both geologic geodetic strain rate data; catalogs through 2012 include assessments of locations magnitudes; adaptive smoothing more fully account spatial clustering 22 ground motion some which consider than double shaking...
In this paper we present a methodology, data, and regression equations for calculating the fault rupture hazard at sites near steeply dipping, strike-slip faults. We collected digitized on-fault off-fault displacement data 9 global strike- slip earthquakes ranging from moment magnitude M 6.5 to 7.6 supplemented these with displacements 13 compiled by Wesnousky (2008), who considers events up 7.9. Displacements on primary fall off ends are often measured in meters, while secondary (off-...
ABSTRACT We present the 2023 U.S. Geological Survey time-independent earthquake rupture forecast for conterminous United States, which gives authoritative estimates of magnitude, location, and time-averaged frequency potentially damaging earthquakes throughout region. In addition to updating virtually all model components, a major focus has been provide better representation epistemic uncertainties. For example, we have improved multifault ruptures, both in terms allowing more less fault...
We update the ground-motion characterization for 2023 National Seismic Hazard Model (NSHM) conterminous United States. The includes use of new models (GMMs) in Cascadia subduction zone; an adjustment to central and eastern States (CEUS) GMMs reduce misfits with observed data; updated boundary application shallow, crustal earthquakes active tectonic regions (i.e. western (WUS)) stable continental CEUS); improved site response deep sedimentary basins WUS CEUS. Site updates include basin...
We used recordings of the M 6.8 Nisqually earthquake and its L 3.4 aftershock to study site response basin effects for 35 locations in Seattle, Washington. determined amplification from Fourier spectral ratios recorded horizontal ground motions, referenced a soft-rock site. Soft-soil sites (generally National Earthquake Hazard Reduction Program [NEHRP] class E) on artificial fill young alluvium have largest 1-Hz amplifications (factors 3–7) both mainshock aftershock. These are correlated...
The U.S. Geological Survey (USGS) recently completed new probabilistic seismic hazard maps for the United States, including Alaska and Hawaii. These form basis of component design used in 1997 edition NEHRP Recommended Provisions Seismic Regulations New Buildings Other Structures, prepared by Building Safety Council published FEMA. depict peak horizontal ground acceleration spectral response at 0.2, 0.3, 1.0 sec periods, with 10%, 5%, 2% probabilities exceedance 50 years, corresponding to...
Abstract A small aperture (≈300 m), four-station array was deployed in Sunnyvale, California for 5 days to record aftershocks of the Loma Prieta earthquake October 1989. The purpose study seismic response alluvium-filled Santa Clara Valley and role surface waves shaking sedimentary basins. Strong-motion records mainshock indicate that produced peak velocities displacements at some sites Valley. We use recordings from dense determine apparent velocity azimuth propagation various arrivals...