Science Explorer
Exploring: Earthquakes
Earthquakes
The latest and historical earthquakes, hazards information, educational resources, maps, seismographic stations and real-time recording, current research in plain language, data, software and derived products.
Lakes as paleoseismic records in a seismically-active, low-relief area (Rieti Basin, central Italy)
Small lakes in low relief areas are atypical candidates for studies on paleoseismicity, but their sediments can contain seismically induced event layers (seismites) generated through strong ground shaking, sediment transport, hydrological reorganization and/or changes in groundwater chemistry and flow. Lakes Lungo and Ripasottile are shallow lakes...
How physics‐based earthquake simulators might help improve earthquake forecasts
Questions have persisted on the usefulness of physics‐based earthquake simulators with respect to forecasting earthquakes, due mostly to the inevitable assumptions, approximations, and uncertainties. Whether any model is reliable or trustworthy depends entirely on what questions we are asking of it, so the point of this article is to outline a...
Stratigraphic and structural relations in trench exposures and geomorphology at the Big Burn, Lily Lake, and Lester Ranch sites, Bear River Fault Zone, Utah and Wyoming
This report provides trench photomosaics, logs and related site information, age data, and earthquake event evidence from three paleoseismic trench sites on the Bear River Fault Zone. Our motivation for studying the Bear River Fault Zone—a nascent normal fault in the Rocky Mountains east of the Basin and Range physiographic province—is twofold: (1...
Rupture model of the M5.8 Pawnee, Oklahoma earthquake from regional and teleseismic waveforms
The 2016 M5.8 Pawnee, Oklahoma earthquake is the largest earthquake to have been induced by wastewater disposal. We infer the coseismic slip history from analysis of apparent source time functions and inversion of regional and teleseismic P‐waveforms, using aftershocks as empirical Green's functions. The earthquake nucleated on the shallow part of...
Four major Holocene earthquakes on the Reelfoot fault recorded by sackungen in the New Madrid seismic zone, USA
Three sequences of well-documented, major ~M7+ earthquakes (1811-1812 CE, ~1450 CE, and ~900 CE) in the New Madrid seismic zone, USA, contribute significantly to seismic hazard in the region. However, it is unknown whether this <550 yr recurrence interval has been constant throughout the Holocene given limited geomorphic evidence of prior...
California’s exposure to volcanic hazards
The potential for damaging earthquakes, landslides, floods, tsunamis, and wildfires is widely recognized in California. The same cannot be said for volcanic eruptions, despite the fact that they occur in the state about as frequently as the largest earthquakes on the San Andreas Fault. At least ten eruptions have taken place in the past 1,000...
Three-dimensional basin and fault structure from a detailed seismic velocity model of Coachella Valley, Southern California
The Coachella Valley in the northern Salton Trough is known to produce destructive earthquakes, making it a high seismic hazard area. Knowledge of the seismic velocity structure and geometry of the sedimentary basins and fault zones is required to improve earthquake hazard estimates in this region. We simultaneously inverted first P wave travel...
Rayleigh wave ellipticity measurement uncertainty across the IRIS/USGS and New China Digital Seismograph Networks
Long-period Rayleigh wave horizontal to vertical amplitude (H/V) ratios at a station provide information about local earth structure that is complementary to phase velocity. However, a number of studies have observed that significant scatter appears in these measurements making it difficult to use H/V ratio measurements to resolve earth structure...
