Using the simple ETAS branching model of seismicity, which assumes that each earthquake can trigger other earthquakes, we quantify the role played by the cascade of triggered seismicity in controlling the rate of aftershock decay as well as the overall level of seismicity in the presence of a constant external seismicity source. We show that, in this model, the fraction of earthquakes in the po...

As part of an effort to develop a systematic methodology for earthquake forecasts, we use a simple model of seismicity based on interacting events which may trigger a cascade of earthquakes, well-known as the Epidemic-Type Aftershock Sequence model). The ETAS model is constructed on a (bare) Omori’s law, the Gutenberg-Richter law and the idea that large events trigger more numerous aftershocks....

Stress focusing in a proposed heel-shaped model reasonably explains the occurrence of the largest onland earthquake (MW 7.6) in Taiwan’s history. The epicenter of the mainshock was located in a low-seismicity block, where, historically, large earthquakes have not been documented for the past century. Spatial variations in crustal deformation reported in Global Positioning System surveys suggest...

Changes in seismicity rates, whether of tectonic or of induced origin, can readily be identified in regions where background rates are low but are difficult to detect in seismically active regions. We present a novel method to identify likely induced seismicity in tectonically active regions based on short-range spatiotemporal correlations between changes in fluid injection and seismicity rates...

Fracture and fault zones can channel fluid flow and transmit injection-induced pore pressure changes over large distances (>km), at which seismicity is rarely suspected to be human induced. We use seismicity analysis and hydrogeological models to examine the role of seismically active faults in inducing earthquakes. We analyze a potentially injection-induced earthquake swarm with three events a...

Mature seismic gaps are defined here as gaps in which a possible precursor to a future event has been identified. The seismic potential of these seismic gaps is enhanced relative to immature seismic gaps. The seismic gap hypothesis by itself provides an excellent means of narrowing spatial limits along plate boundaries within which the great earthquakes of the next several decades are expected....

Recent studies of reservoir-induced seismicity have led to a better understanding of the seismogenic crust. These studies reveal that many parts of the seismogenic crust are critically stressed and small strength changes induced by reservoir impoundment can lead to seismicity. In the vicinity of the reservoir impoundment causes an immediate undrained response to the loading, and a delayed respo...

Through a detailed analysis of seismicity at the base of the transition zone, we obtain an updated value of the maximum reliable depth of confirmed seismicity, we investigate regional variation in the maximum depth of seismicity among those Wadati-Benioff zones which reach the bottom of the transition zone, and we attempt to quantify the maximum possible rate of seismic release in the lower man...

Background Gaucher et al. (2015) provide an overview on published methods employed for modelling induced seismicity in geothermal reservoirs. Here I focus exclusively on the rateand state-dependent theory of Dieterich (1994), further referred to as RST for modelling fluid injection induced seismicity. For simplicity, I consider the case of fluid injection at the origin in a medium with isotropi...

The cause of intermediate-depth (> 40 km) seismicity in subduction zones is not well understood. The viability of proposed mechanisms, which include dehydration embrittlement, shear instabilities and the presence of fluids in general, depends significantly on local conditions, including pressure, temperature and composition. The wellinstrumented and well-studied subduction zone below Northern J...