Publications
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Variability of displacement at a point: Implications for earthquake‐size distribution and rupture hazard on faults
To investigate the nature of earthquake‐magnitude distributions on faults, we compare the interevent variability of surface displacement at a point on a fault from a composite global data set of paleoseismic observations with the variability expected from two prevailing magnitude–frequency distributions: the truncated‐exponential model and the characteristic‐earthquake model. We use forward modeli
Authors
Suzanne Hecker, N. A. Abrahamson, Kathryn Wooddell
Missing great earthquakes
The occurrence of three earthquakes with moment magnitude (Mw) greater than 8.8 and six earthquakes larger than Mw 8.5, since 2004, has raised interest in the long-term global rate of great earthquakes. Past studies have focused on the analysis of earthquakes since 1900, which roughly marks the start of the instrumental era in seismology. Before this time, the catalog is less complete and magnitud
Authors
Susan E. Hough
Seismicity of the Earth 1900–2010 Himalaya and vicinity
Seismicity in the Himalaya region predominantly results from the collision of the India and Eurasia continental plates, which are converging at a relative rate of 40–50 mm/yr. Northward underthrusting of India beneath Eurasia generates numerous earthquakes and consequently makes this area one of the most seismically hazardous regions on Earth. The surface expression of the plate boundary is marked
Authors
Bethan Turner, Jennifer Jenkins, Rebecca Turner, Amy Parker, Alison Sinclair, Sian Davies, Gavin P. Hayes, Antonio Villaseñor, Rirchard L. Dart, Arthur C. Tarr, Kevin P. Furlong, Harley M. Benz
Fine-scale delineation of the location of and relative ground shaking within the San Andreas Fault zone at San Andreas Lake, San Mateo County, California
The San Francisco Public Utilities Commission is seismically retrofitting the water delivery system at San Andreas Lake, San Mateo County, California, where the reservoir intake system crosses the San Andreas Fault (SAF). The near-surface fault location and geometry are important considerations in the retrofit effort. Because the SAF trends through highly distorted Franciscan mélange and beneath m
Authors
R. D. Catchings, M. J. Rymer, M. R. Goldman, C.S. Prentice, R.R. Sickler
Characterization of the Hosgri Fault Zone and adjacent structures in the offshore Santa Maria Basin, south-central California
The Hosgri Fault Zone trends subparallel to the south-central California coast for 110 km from north of Point Estero to south of Purisima Point and forms the eastern margin of the present offshore Santa Maria Basin. Knowledge of the attributes of the Hosgri Fault Zone is important for petroleum development, seismic engineering, and environmental planning in the region. Because it lies offshore alo
Authors
C. Richard Willingham, Jan D. Rietman, Ronald G. Heck, William R. Lettis
Seismic imaging of the Waltham Canyon fault, California: comparison of ray‐theoretical and Fresnel volume prestack depth migration
Near‐vertical faults can be imaged using reflected refractions identified in controlled‐source seismic data. Often theses phases are observed on a few neighboring shot or receiver gathers, resulting in a low‐fold data set. Imaging can be carried out with Kirchhoff prestack depth migration in which migration noise is suppressed by constructive stacking of large amounts of multifold data. Fresnel vo
Authors
Klaus Bauer, Trond Ryberg, Gary S. Fuis, Stefan Lüth
Size distribution of Parkfield’s microearthquakes reflects changes in surface creep rate
The nucleation area of the series of M6 events in Parkfield has been shown to be characterized by low b-values throughout the seismic cycle. Since low b-values represent high differential stresses, the asperity structure seems to be always stably stressed and even unaffected by the latest main shock in 2004. However, because fault loading rates and applied shear stress vary with time, some degree
Authors
Theresa Tormann, Stefan Wiemer, Sabrina Metzger, Andrew J. Michael, Jeanne L. Hardebeck
Implications of the Mw9.0 Tohoku-Oki earthquake for ground motion scaling with source, path, and site parameters
The Mw9.0 Tohoku-oki Japan earthquake produced approximately 2,000 ground motion recordings. We consider 1,238 three-component accelerograms corrected with component-specific low-cut filters. The recordings have rupture distances between 44 km and 1,000 km, time-averaged shear wave velocities of VS30 = 90 m/s to 1,900 m/s, and usable response spectral periods of 0.01 sec to >10 sec. The data suppo
Authors
Jonathan P. Stewart, Saburoh Midorikawa, Robert W. Graves, Khatareh Khodaverdi, Tadahiro Kishida, Hiroyuki Miura, Yousef Bozorgnia, Kenneth W. Campbell
Near real-time monitoring of volcanic surface deformation from GPS measurements at Long Valley Caldera, California
Long Valley Caldera in eastern California is an active volcanic area and has shown continued unrest in the last three decades. We have monitored surface deformation from Global Positioning System (GPS) data by using a projection method that we call Targeted Projection Operator (TPO). TPO projects residual time series with secular rates and periodic terms removed onto a predefined spatial pattern.
Authors
Kang Hyeun Ji, Thomas A. Herring, Andrea L. Llenos
Global earthquake fatalities and population
Modern global earthquake fatalities can be separated into two components: (1) fatalities from an approximately constant annual background rate that is independent of world population growth and (2) fatalities caused by earthquakes with large human death tolls, the frequency of which is dependent on world population. Earthquakes with death tolls greater than 100,000 (and 50,000) have increased with
Authors
Thomas L. Holzer, James C. Savage
Workshop on New Madrid geodesy and the challenges of understanding intraplate earthquakes
On March 4, 2011, 26 researchers gathered in Norwood, Massachusetts, for a workshop sponsored by the U.S. Geological Survey and FM Global to discuss geodesy in and around the New Madrid seismic zone (NMSZ) and its relation to earthquake hazard. The group addressed the challenge of reconciling current geodetic measurements, which show low present-day surface strain rates, with paleoseismic evidence
Authors
Oliver Boyd, Eric Calais, John Langbein, Harold Magistrale, Seth Stein, Mark Zoback
Working with strainmeter data
The Plate Boundary Observatory (PBO), the geodetic component of the U.S. National Science Foundation–funded Earthscope program, includes 75 borehole and 6 laser strainmeters (http://pbo.unavco.org). The strainmeters are installed at several locations: on the Cascadia forearc in Washington state and on Vancouver Island, Canada; in arrays of two to nine instruments along the North American–Pacific p
Authors
Kathleen M. Hodgkinson, Duncan Agnew, Evelyn A. Roeloffs