Fluid injection into deep wellbores can increase pore pressure, reduce effective stress, and trigger earthquakes. The extent of the seismogenic response to injection provides insight into how close faults are to failure in the injection-affected area. The seismogenic response to injection operations in hydrocarbon basins is examined in California and Oklahoma. Changes in spatial and temporal se...

Predictions of earthquakes that are based on observations of precursory seismicity cannot depend on the average properties of the seismicity, such as the Gutenberg-Richter (G-R) distribution. Instead it must depend on the fluctuations in seismicity. We summarize the observational data of the fluctuations of seismicity in space, in time, and in a coupled space-time regime over the past 60 yr in ...

We examine 20-yr data sets of seismic activity from 10 volcanic areas in the western United States for annual periodic signals (seasonality), focusing on large calderas (Long Valley caldera and Yellowstone) and stratovolcanoes (Cascade Range). We apply several statistical methods to test for seasonality in the seismic catalogs. In 4 of the 10 regions, statistically significant seasonal modulati...

The cellular seismology (CS) method of Kafka (2002, 2007) is presented as a least-astonishing null hypothesis that serves as a useful standard of comparison for other, more complex, spatial forecast methods (i.e., methods that forecast the locations, but not the times, of earthquakes). Spatial forecast methods based on analyses of earthquakes in California, such as that of Ebel et al. (2007) an...

The extent to which ongoing seismicity in intraplate regions represents long-lived aftershock activity is unclear. We examined historical and instrumental seismicity in the New Madrid central U.S. region to determine whether present-day seismicity is composed predominantly of aftershocks of the 1811-1812 earthquake sequence. High aftershock productivity is required both to match the observation...

hospitals have a long history throughout the history of medicine. first hospitals are originated from persia in ancient times in the sassanid dynasty (2nd to 6th century ad). after the advent of islam in persia (iran) in 637 ad, medical knowledge and also hospitals were ourished and advanced by persian scholars. shiraz azodi hospital and university was one of the important hospitals in persia....

Earthquakes may be induced by a wide range of anthropogenic activities such as mining, fluid injection and extraction, and hydraulic fracturing. In recent years, the increased occurrence of induced seismicity and the impact of some of these earthquakes on the built environment have heightened both public concern and regulatory scrutiny, motivating the need for a framework for the management of ...

The 1999 Chi-Chi earthquake (MW=7.6; ML=7.3) ruptured in an area considered unusual in that, historically, large earthquakes have been unheard of and the background seismicity are low. A detailed investigation of the crustal characteristics based on seismicity, subsurface structures and GPS surveys shows that crustal strength in the low-seismicity block was most likely stronger than in the surr...