"ShakeMaps" - instant maps of earthquake shaking

A Structural VP Model of the Salton Trough, California, and Its Implications for Seismic Hazard

“…The ground motions predicted in the southern portion of the trough, including the communities of Brawley, El Centro, and Mexicali, are comparable to those predicted by the TeraShake project . The peak velocity values predicted along the fault by our simulation are nearly three times the magnitude of peak velocities produced by the 1994 Northridge earthquake (peak velocities at Northridge were approximately 1.20 m sec ‫1מ‬ ) (Wald, 1999;Wald et al, 2000), which resulted in over $40 billion in damages and 57 deaths north of Los Angeles. The area in the Salton Trough affected by amplified surface velocity values is also much larger than in the Northridge event.…”

Ground-Motion Observations of the 2014 South Napa Earthquake

“…We consider ground motions recorded from the South Napa earthquake as reported by the Northern California Seismic System, University of California (Berkeley), and U.S. Geological Survey (Menlo Park) and compiled in the ShakeMap (Wald et al, 2000, see Data and Resources; Fig. 1); using the distance metric R rup , the closest distance to the rupture plane, as calculated in the ShakeMap from the initial finite-fault inversion of Dreger et al (2015).…”

“…Using the ground-motion data compiled and reported by ShakeMap (Wald et al, 2000), we examine the peak ground acceleration (PGA) and peak ground velocity (PGV), as well as the pseudospectral acceleration (PSA) at periods of 0.3, 1.0, and 3.0 s. At the higher frequencies, especially PGA, data recorded at close distances (within ∼20 km) are very consistent with the GMPEs, implying a stress drop for this event similar to the median for California, that is, 5 MPa (Baltay and Hanks, 2014). At all frequencies, the attenuation with distance is stronger than the GMPEs would predict, which suggests the attenuation in the Napa and San Francisco Bay delta region is stronger than the average attenuation in California.…”

The Sidebar Computer Program, a seismic-shaking intensity meter: users' manual and software description

“…ShakeMap (Figure 2) is a map of seismic intensity for the whole region (Wald et al, 1999b(Wald et al, , 2000. One could say that it is a map of how brightly the light bulb is shining into every corner of the region, or of how loudly a single clap of thunder sounds to millions of different listeners, near or far, from a single flash of lightning.…”