Near-source strong motion velocity records and teleseismic short-period P waveforms are modeled to obtain the spatial and temporal distribution of slip for the 1984 Morgan Hill earthquake. Both forward modeling and constrained, leastsquares inversion techniques are used to interpret the strong motion velocity waveforms in the frequency range of approximately 0.2 to 2.0 Hz. These data support a ...

S U M M A R Y We present a re-evaluation of the seismological properties of the Aleutian ‘tsunami earthquake’ of 1946 April 1, characterized by a deceptively low conventional magnitude (7.4) in view of its catastrophic tsunami, both in the near and far fields. Relocation of 40 aftershocks show that the fault zone extends a minimum of 181 km along the Aleutian trench, in a geometry requiring a b...

Static coseismic offsets >1 mm are observed up to 7800 km away from the great Sumatra-Andaman earthquake of 26 Dec. 2004 using global GPS network data. We investigate the rupture process based on far-field continuous GPS data. To reduce error in the coseismic offset estimates due to post-seismic deformation in the days following the main shock, we simultaneously fit a model of coand postseismic...

After an earthquake, the earliest deformation signals are not expected to be carried by the fastest (P) elastic waves but by the speed-of-light changes of the gravitational field. However, these perturbations are weak and, so far, their detection has not been accurate enough to fully understand their origins and to use them for a highly valuable rapid estimate of the earthquake magnitude. We sh...

The dense networks of strong-ground-motion instruments in Japan (KNET and KiK-net) provide a means of direct visualization of regional wave propagation during large earthquakes. For the 2000 Tottori-ken Seibu earthquake (Mw 6.6) in western Japan, snapshots of ground motion, derived directly from interpolation of a large number of array observations, demonstrate clearly the nature of the source ...

Focusing on soil liquefaction, the seismic records during the Niigata-ken earthquake in 1964, the southern Hyogo prefecture earthquake in 1995 and the 2011 off the Pacific coast of Tohoku earthquake are analyzed by the non-stationary Fourier spectra. The shift of dominant frequency in the seismic record of Kawagishi-cho during the Niigata-ken earthquake is evaluated based on the time-variant pr...

The recent 2011 Mw 9.0 Tohoku, Japan, and the 2004 Mw 9.15 Sumatra–Andaman superquakes have humbled many in earthquake research. Neither region was thought capable of earthquakes exceeding Mw ∼ 8:4. Appealing proposed relationships to predict the size of earthquakes in subduction zones, such as that between earthquake magnitude and parameters such as lower plate age and convergence rate (Ruff a...

The M9 Tohoku earthquake offshore Japan that occurred on May 11, 2011 triggered strong local and regional shaking as well as a large-scale tsunami that caused major damage in both the nearand far-field. The Japanese earthquake and tsunami warning systems were able to detect and locate the earthquake; however information regarding the focal mechanism of the event was unknown until the moment ten...

To estimate the fault dimension of an earthquake in real time, we present a methodology to classify seismic records into near-source or far-source records. Characteristics of ground motion, such as peak ground acceleration, have a strong correlation with the distance from a fault rupture for large earthquakes. This study analyzes peak ground motions and finds the function that best classifies n...