An earthquake sequence occurred in the Atacama region of Chile throughout September 2020. The initiated by a mainshock magnitude Mw= 6.9, followed 17 hours later 6.4 aftershock. lasted several weeks, during which more than thousand events larger Ml= 1 occurred, including earthquakes magnitudes between 5.5 and 6.4. Using dense network that includes broad-band, strong motion GPS sites, we study d...

Abstract The clearest statistical signal in aftershock locations is that most aftershocks occur close to their mainshocks. More precisely, are triggered at distances following a power-law decay distance (Felzer and Brodsky, 2006). This kernel used epidemic-type sequence (ETAS) modeling typically assumed be isotropic, even though individual sequences show more clustered occurrence. assumption of...

SUMMARY The Gutenberg–Richter (GR) and the Omori–Utsu (OU) law describe earthquakes’ energy release temporal clustering are thus of great importance for seismic hazard assessment. Motivated by experimental results, which indicate stress-dependent parameters, we consider a combined global data set 127 main shock–aftershock sequences perform systematic study relationship between shock-induced str...

Assume that each earthquake can produce a series of aftershock independently of its size according to its “local” Omori’s law with exponent 1+θ. Each aftershock can itself trigger other aftershocks and so on. The global observable Omori’s law is found to have two distinct power law regimes, the first one with exponent p− = 1− θ for time t < t ∗ ∼ κ−1/θ, where 0 < 1−κ < 1 measures the fraction o...

The time variation of crustal velocities in tectonic regions is most reasonably attributed to stressinduced variations in crack porosity. The decrease in V•,/Vs before arthquakes is due primarily to a large decrease in Vp. This supports the Nur dilatancy hypothesis but not the effective stress hypothesis. New data from the San Fernando region verify the Vp drop, show that this drop cannot be en...

The question whether the preparation process of foreshocks and mainshocks is diierent from other earthquakes is of great interest with regard to earthquake predictability. We show that the most conspicuous properties of earthquake clustering can be explained without assuming any diierences in the initiation processes. In particular, the Gutenberg-Richter law as well as the Omori law for foresho...

Fault slip during plate boundary earthquakes releases a portion of the shear stress accumulated due to frictional resistance to relative plate motions. Investigation of 101 large [moment magnitude (Mw) ≥ 7] subduction zone plate boundary mainshocks with consistently determined coseismic slip distributions establishes that 15 to 55% of all master event-relocated aftershocks with Mw ≥ 5.2 are loc...

The region of Beni-Ilmane (District of M'sila, north-central Algeria) was the site of an earthquake sequence that started on 14 May 2010. This sequence, which lasted several months, was triggered by conjugate E-W reverse and N-S dextral faulting. To image the crustal structure of these active faults, we used a set of 1406 well located aftershocks events and applied the local tomography software...

We present and discuss the spatial distribution of more than 1000 aftershocks of the largest continental intraplate earthquake to occur during the modern seismological period. The data were recorded on a network of eight portable digital seismographs deployed for 3 weeks starting 17 days after the mainshock. We have calculated high-quality single-event locations, based on a 1D velocity model de...