Southern California Earthquake Center Geologic Vertical Motion Database

Comprehensive analysis of earthquake source spectra in southern California

[1] We compute and analyze P wave spectra from earthquakes in southern California between 1989 and 2001 using a method that isolates source-, receiver-, and pathdependent terms. We correct observed source spectra for attenuation using both fixed and spatially varying empirical Green’s function methods. Estimated Brune-type stress drops for over 60,000ML = 1.5 to 3.1 earthquakes range from 0.2 t...

Earthquake clusters in southern California I: Identification and stability

[1] We use recent results on statistical analysis of seismicity to present a robust method for comprehensive detection and analysis of earthquake clusters. The method is based on nearest-neighbor distances of events in space-time-energy domain. The method is applied to a 1981–2011 relocated seismicity catalog of southern California having 111,981 events with magnitudes m ≥ 2 and corresponding s...

Earthquake Monitoring in Southern California for Seventy-Seven Years

The Southern California Seismic Network (SCSN) has produced the SCSN earthquake catalog from 1932 to the present, a period of more than 77 yrs. This catalog consists of phase picks, hypocenters, and magnitudes. We present the history of the SCSN and the evolution of the catalog, to facilitate user understanding of its limitations and strengths. Hypocenters and magnitudes have improved in qualit...

The potential for earthquake early warning in southern California.

Earthquake mitigation efforts in the United States currently use long-term probabilistic hazard assessments and rapid post-earthquake notification to reduce the potential damage of earthquakes. Here we present the seismological design for and demonstrate the feasibility of a short-term hazard warning system. Using data from past earthquakes, we show that our Earthquake Alarm System (ElarmS) cou...

Full-Wave Ground Motion Forecast for Southern California