The 1911 M 6.6 Calaveras Earthquake: Source Parameters and the Role of Static, Viscoelastic, and Dynamic Coulomb Stress Changes Imparted by the 1906 San Francisco Earthquake

2009 ◽  
Vol 99 (3) ◽  
pp. 1746-1759 ◽  
Author(s):  
D. I. Doser ◽  
K. B. Olsen ◽  
F. F. Pollitz ◽  
R. S. Stein ◽  
S. Toda
2021 ◽  
Author(s):  
Simone Cesca ◽  
Carla Valenzuela Malebrán ◽  
José Ángel López-Comino ◽  
Timothy Davis ◽  
Carlos Tassara ◽  
...  

<p> A complex seismic sequence took place in 2014 at the Juan Fernández microplate, a small microplate located between Pacific, Nazca and Antarctica plates. Despite the remoteness of the study region and the lack of local data, we were able to resolve earthquake source parameters and to reconstruct the complex seismic sequence, by using modern waveform-based seismological techniques. The sequence started with an exceptional Mw 7.1-6.7 thrust – strike slip earthquake doublet, the first subevent being the largest earthquake ever recorded in the region and one of the few rare thrust earthquakes in a region otherwise characterized by normal faulting and strike slip earthquakes. The joint analysis of seismicity and focal mechanisms suggest the activation of E-W and NE-SW faults or of an internal curved pseudofault, which is formed in response to the microplate rotation, with alternation of thrust and strike-slip earthquakes. Seismicity migrated Northward in its final phase, towards the microplate edge, where a second doublet with uneven focal mechanisms occurred. The sequence rupture kinematics is well explained by Coulomb stress changes imparted by the first subevent. Our analysis show that compressional stresses, which have been mapped at the northern boundary of the microplate, but never accompanied by large thrust earthquakes, can be accommodated by the rare occurrence of large, impulsive, shallow thrust earthquakes, with a considerable tsunamigenic potential.</p>


2007 ◽  
Vol 40 (4) ◽  
pp. 2008
Author(s):  
P. M. Paradisopoulou ◽  
E. E. Papadimitriou ◽  
V. G. Karakostas ◽  
A. Kilias

The study of static Coulomb Stress changes requires initially the collection of information on the major active faults in a study area concerning their geometry and kinematic properties and then a series of complex calculation for stress changes that are associated with both coseismic displacements of the stronger events and the tectonic loading on these major faults. The Coulomb Stress Application has been developed as a tool to provide a user-friendly way of entering the necessary data and an efficient way to perform the complex calculations procedure. More specifically the aim of the application is a) the collection of data (catalogues of earthquakes, fault parameters) in a relational database, b) the calculation of earthquake source parameters such as the length and the width of the causative fault, and the coseismic slip by using available scaling laws, and finally, c) the execution of all the necessary programs and scripts (e.g. dis3dop.exe, GMT package) to get a map of static stress changes for an area. Coulomb Stress application provides a way to store these data for a study area and it is a method to perform a series of calculations by plotting a series of maps and examine the results for a number of cases.


2015 ◽  
Vol 22 (5) ◽  
pp. 625-632
Author(s):  
P. A. Toledo ◽  
S. R. Riquelme ◽  
J. A. Campos

Abstract. We study the main parameters of earthquakes from the perspective of the first digit phenomenon: the nonuniform probability of the lower first digit different from 0 compared to the higher ones. We found that source parameters like coseismic slip distributions at the fault and coseismic inland displacements show first digit anomaly. We also found the tsunami runups measured after the earthquake to display the phenomenon. Other parameters found to obey first digit anomaly are related to the aftershocks: we show that seismic moment liberation and seismic waiting times also display an anomaly. We explain this finding by invoking a self-organized criticality framework. We demonstrate that critically organized automata show the first digit signature and we interpret this as a possible explanation of the behavior of the studied parameters of the Tohoku earthquake.


Author(s):  
R. Alac Barut ◽  
J. Trinder ◽  
C. Rizos

On August 17<sup>th</sup> 1999, a M<sub>w</sub> 7.4 earthquake struck the city of Izmit in the north-west of Turkey. This event was one of the most devastating earthquakes of the twentieth century. The epicentre of the Izmit earthquake was on the North Anatolian Fault (NAF) which is one of the most active right-lateral strike-slip faults on earth. However, this earthquake offers an opportunity to study how strain is accommodated in an inter-segment region of a large strike slip fault. In order to determine the Izmit earthquake post-seismic effects, the authors modelled Coulomb stress changes of the aftershocks, as well as using the deformation measurement techniques of Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite System (GNSS). The authors have shown that InSAR and GNSS observations over a time period of three months after the earthquake combined with Coulomb Stress Change Modelling can explain the fault zone expansion, as well as the deformation of the northern region of the NAF. It was also found that there is a strong agreement between the InSAR and GNSS results for the post-seismic phases of investigation, with differences less than 2mm, and the standard deviation of the differences is less than 1mm.


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