A technique for searching full model space that was applied to measurements of anomalously split normal modes showed a robust pattern of P-wave and S-wave anisotropy in the inner core. The parameter describing P-wave anisotropy changes sign around a radius of 400 kilometers, whereas S-wave anisotropy is small in the upper two-thirds of the inner core and becomes negative at greater depths. Our ...

Earthquake early warning studies are shifting real-time seismology in earthquake science. They provide methods to rapidly assess earthquakes to predict damaging ground shaking. Preventing false alarms from these systems is key. Here we developed a simple, robust algorithm, Authorizing GRound shaking for Earthquake Early warning Systems (AGREEs), to reduce falsely issued alarms. This is a networ...

--For many years, large explosions within the Caltech seismic network have occurred periodically at a quarry near Corona (75 km southeast of Pasadena) and at the Eagle Mountain iron mine (240 km east of Pasadena). Explosions have taken place almost daily since 1948 at Eagle Mountain. The long-established station at Hayfield, very close to the mine, permits accurate determinations of apparent ve...

ABSTRACT The moment magnitude (Mw) ?7 earthquake that struck Charleston, South Carolina, on 31 August 1886 is the largest historical in United States east of Appalachian Mountains. fault(s) ruptured during this has never been conclusively identified, and conflicting fault models have proposed. Here we interpret reprocessed seismic reflection profiles, legacy aeromagnetic data, newly collected g...

The Trans-Mexican Volcanic Belt (TMVB) is a calc-alkaline volcanic arc cut by different active crustal fault systems that have originated several destructive historical earthquakes. Located in the central part of Mexico this region offers exceptional climatic, and fertility soil conditions, which reason why more than 50% Mexican population now live here, increasing seismic risk. Determining pot...

We propose a new algorithm to rapidly determine earthquake source and ground-motion parameters for earthquake early warning (EEW). This algorithm uses the acceleration, velocity, and displacement waveforms of a single three-component broadband (BB) or strong-motion (SM) sensor to perform real-time earthquake/noise discrimination and near/far source classification. When an earthquake is detected...

We present estimates of future earthquake rate density (probability per unit area, time, and magnitude) on a 0.1degree grid for a region including California and Nevada, based only on data from past earthquakes. Our long-term forecast is not explicitly time-dependent, but it can be updated at any time to incorporate information from recent earthquakes. The present version, founded on several de...