S U M M A R Y Geometrical properties of an earthquake population can be described by summation of seismic potency tensors that provide a strain-based description of earthquake focal mechanisms. We apply this method to∼170 000 potency tensors for 0<ML ≤ 5 southern California earthquakes recorded between January 1984 and June 2003. We compare summed tensors for populations defined by faulting reg...

[1] Arrival-time data from 453 local earthquakes and 6 explosions at Parkfield, CA, are inverted for earthquake locations and three-dimensional Vp and Vp/Vs structure. The structure is dominated by the velocity contrast across the SAF, with the southwest side about 20–25% faster, consistent with previous studies. Nearly all the earthquakes occur almost directly beneath the fault trace. We find ...

[1] While it is agreed that the great Sumatra earthquake of December 26, 2004 was among the largest earthquakes of the past century, there has been disagreement on how large it was, which part of the fault ruptured, and how the rupture took place. We present a centroid-moment-tensor (CMT) analysis of the earthquake in which multiple point sources are used in the inversion to mimic a propagating...

Several recent studies have presented evidence that significant induced earthquakes occurred in a number of oil-producing regions during the early and mid-twentieth century related to either production or wastewater injection. We consider whether the 21 July 1952 Mw 7.5 Kern County earthquake might have been induced by production in the Wheeler Ridge oil field. The mainshock, which was not prec...

In a spirit akin to the sandpile model of selforganized criticality, we present a simple statistical model of the cellular-automaton type which simulates the role of an asperity in the dynamics of a one-dimensional fault. This model produces an earthquake spectrum similar to the characteristic-earthquake behaviour of some seismic faults. This model, that has no parameter, is amenable to an alge...

Sediments tell a tsunami story Trying to understand where major earthquakes and tsunamis might occur requires analysis of the sediments pouring into a subduction zone. Thick sediments were expected to limit earthquake and tsunami size in the Sumatran megathrust event in 2004, but the magnitude 9.2 earthquake defied expectations. Hüpers et al. analyzed sediments recovered from the Sumatran megat...

The 1999 Izmit earthquake (17/08/1999, Mw=7.4) was one of the largest earthquakes to occur in northwestern Turkey during the past 100 years. This earthquake occurred along the Izmit-Sapanca fault within the Northern Anatolian Fault Zone. Variations in the generalized fractal dimensions (Dq) of clustering in time and space, the Gutenberg-Richter b value, and earthquake frequency (N) are evaluate...

[1] We have developed a systematic nonlinear inversion method for estimating rupture propagation and the underlying dynamic parameters for large historical earthquakes. The rupture modeling is carried out using a three-dimensional finite-difference method, and the inversion is implemented by a neighbourhood algorithm, minimizing the misfit between computed and observed near-fault seismograms. W...

The Subdue structural discovery system is being used as the Data Mining tool to study the "Orizaba Fault" located in Mexico, as part of a research project of the geologist Dr. Burke Burkart. We analyze the information of the Earthquake Database to discover if the earthquake activity in the area is related to the fault. We experimented with different samples of data mainly using two heuristics t...

Earthquakes occur in regions with intense seismic activities and cause life and property losses. Predicting earthquakes, identifying deformations and decreasing earthquake effects have been major subjects for scientists, engineers, and authorities. One of the theories used for identifying location changes during an earthquake is the elastic half-space model. Recently, the Global Navigation Sate...