The 2016 Kumamoto earthquakes in Kyushu, Japan, started with a magnitude (M) 6.5 quake on April 14 on the Hinagu fault zone (FZ), followed by active seismicity including an M6.4 quake. Eventually, an M7.3 quake occurred on April 16 on the Futagawa FZ. We investigated if any sign indicative of the M7.3 quake could be found in the space–time changes in seismicity after the M6.5 quake. As a qualit...

In the year 2000, an anomalous sequence of off-fault seismicity was detected near Lake Pillsbury in northern California. The seismicity was interpreted by Hayes et al. (2005, 2006) to be associated with a dike injection. I completed a gravity survey over the location of the seismicity and used that data in gravity modeling, to test the hypothesis that the seismicity was directly linked to the i...

The null hypothesis in assessing earthquake predictions is often, loosely speaking, that the successful predictions are chance coincidences. To make this more precise requires specifying a chance model for the predictions and/or the seismicity. The null hypothesis tends to be rejected not only when the predictions have merit, but also when the chance model is inappropriate. In one standard appr...

The concept of background seismicity is strictly related to the identification of spontaneous and triggered earthquakes. The definition of foreshocks, main shocks and aftershocks is currently based on procedures depending on parameters whose values are notoriously assumed by subjective criteria. We propose a method for recognizing the background and the induced seismicity statistically. Rather ...

We analyzed the historical seismicity in southern California to develop a rational approach for calculating the seismic hazard from background seismicity of magnitude 6.5 or smaller. The basic assumption for the approach is that future earthquakes will be clustered spatially near locations of historical mainshocks of magnitudes equal to or greater than 4. We analyzed the declustered California ...

Microearthquake (MEQ) occurrence surrounding the injection well DV11 in Unit 18 of the Southeast (SE) Geysers is investigated. Seismicity rates are compared to the injection rate, and to flow rates in nearby steam extraction wells, which were monitored during the Unit 18 Cooperative Injection Test in 1994 and 1995. The seismicity rate is seen to mirror both injection and production rates, altho...

Induced seismicity has been observed near Monticello Reservoir, South Carolina, since December 1977. Deployment of a seismic network before impoundment allowed for detection and accurate location of pursuant seismicity since its inception. Corroborative fault-plane solutions, together with geological and borehole data on fracture orientations, made it possible to determine the structures associ...

Numerical models including one or more faults in a rheologically stratified lithosphere show that climate-induced variations in ice and water volumes on Earth's surface considerably affect the slip evolution of both thrust and normal faults. In general, the slip rate and hence the seismicity of a fault decreases during loading and increases during unloading. Here, we present several case studie...