The January 25th, 2014 Kebumen earthquake: A normal faulting in subduction zone of Southern Java

2017 ◽  
Author(s):  
Yopi Ruben Serhalawan ◽  
Dimas Sianipar ◽  
Iman Suardi
Keyword(s):  
Subduction Zone ◽  
Normal Faulting

scholarly journals Normal faulting and mass movement during ridge subduction inferred from porosity transition and zeolitization in the Costa Rica subduction zone

2017 ◽  
Vol 18 (7) ◽  
pp. 2601-2616 ◽  
Author(s):  
Mari Hamahashi ◽  
Elizabeth Screaton ◽  
Wataru Tanikawa ◽  
Yoshitaka Hashimoto ◽  
Kylara Martin ◽  
...  
Keyword(s):  
Costa Rica ◽  
Subduction Zone ◽  
Mass Movement ◽  
Normal Faulting ◽  
Ridge Subduction

scholarly journals The large normal-faulting Mariana Earthquake of April 5, 1990 in uncoupled subduction zone

1992 ◽  
Vol 19 (3) ◽  
pp. 297-300 ◽  
Author(s):  
Yasuhiro Yoshida ◽  
Kenji Satake ◽  
Katsuyuki Abe
Keyword(s):  
Subduction Zone ◽  
Normal Faulting

Fault tectonic analysis of aftershocks of the 2011 Tohoku, Japan, earthquake: interaction between three different tectonic domains and approximation of stress magnitude

2020 ◽  
Author(s):  
Pom-yong Choi
Keyword(s):  
Subduction Zone ◽  
Continental Crust ◽  
Focal Mechanism ◽  
Coastal Area ◽  
Pacific Plate ◽  
Japan Meteorological Agency ◽  
Vertical Load ◽  
Normal Faulting ◽  
Stress Tensors ◽  
The Pacific

<p>In order to elucidate the regional variation of stress field in the eastern part of Japan after the 2011 Tohoku earthquake of M=9.3, we tried to analyze focal mechanism data of earthquakes that occurred in 2011, presented by the Japan Meteorological Agency (JMA). Although earthquakes (aftershocks) occurred largely in the offshore area along the subduction zone of the Pacific plate under the North American and Eurasian plates, focal mechanism data presented by JMA are mainly those on land. For fault tectonic analysis, the suggested focal mechanism data are classified into appropriate populations on the basis of clusters and focal depths to reduce the bias and errors of stress tensors resulting from areal stress variation and varying vertical load. According to the results, the stress types of determined stress tensors consist of reverse, wrench and normal faulting ones. As for reverse faulting stresses in which the vertical load is the minimum principal stress axis, those of NW-SE compression prevail, which may be tightly related to northwestward movement of the Pacific plate. Those of E-W compression are determined in the continental crust deeper than about 9 km around Yamagata and in the lower part of subducting oceanic crust. In the Kanagawa and Chiba areas, determined stress tensors display NNW-SSE compression as well as NW-SE and E-W compressions. The NNW-SSE compression seems to be related to the movement of the Philippine Sea plate. Stress tensors of wrench faulting type are found in the continental crust far from the subduction zone of the Pacific plate, displaying NW-SE and E-W compressions in the shallower and deeper parts of crust, respectively. The E-W compression is presumably associated with the Himalayan tectonic domain. Determined stress tensors of normal faulting type show diverse extension directions: NW-SE extension in the coastal area, parallel to the Pacific compression, and E-W or NE-SW extension elsewhere. Especially, numerous focal mechanism data showing normal faulting stresses are present in the coastal area of Fukushima and Ibaraki, from which Poisson’s ratio of shallow crust was determined to be 0.25 to 0.27 using friction lines on Mohr’s circles and focal depths (or corresponding vertical loads). Additional horizontal stress related to the northwestward motion of the Pacific plate was estimated to be 46, 122 and 286 MPa in three groups of 0 to1.5, 1.5 to 4.5 and 3.5 to 11.5 kilometers in depth, respectively.</p>

scholarly journals THE 16 APRIL 2015 MW6.1 EARTHQUAKE SEQUENCE NEAR KASOS ISLAND AT THE EASTERN HELLENIC SUBDUCTION ZONE

2017 ◽  
Vol 50 (3) ◽  
pp. 1163
Author(s):  
A.A. Kiratzi
Keyword(s):  
Subduction Zone ◽  
Broad Band ◽  
Rake Angle ◽  
Source Model ◽  
Strike Slip ◽  
Earthquake Sequence ◽  
Reverse Fault ◽  
Normal Faulting ◽  
Hellenic Subduction Zone ◽  
Finite Fault

Broad band seismic waveforms are used to determine the source model of the 16 April 2015 (UTC 18:07:44) earthquake, Mw6.1, which occurred 14 km SW of Kasos Island, in the eastern Hellenic subduction zone. The mainshock is connected with oblique leftlateral motion on a reverse fault, dipping to SE. Most of the aftershocks are compatible with strike-slip or oblique normal faulting, with the T-axes showing along arc extension. A finite fault slip inversion was performed, allowing for the rake angle to vary across the fault, to capture the variation in the slip vectors. The rupture initiated in the lower crust, at a centroid depth of 23 km, and propagated mainly towards SW. The slip is confined in depth within ~17km and 27km, mainly in a single asperity, with the peak slip of the order of 60 cm. The slip model provided synthetic seismograms which matched satisfactory the observed, and with forward modelling the ShakeMap was calculated. The 2015 Kasos earthquake sequence is compatible with shear motions parallel to the strike of the subduction zone. It provides evidence that part of the deformation in the eastern Hellenic subduction is taken up by the simultaneous operation of reverse faulting and of minor strike-slip and oblique normal faulting, with slip vectors aligned ~ parallel to the Pliny and Strabo Trenches and the long axis of the local bathymetry.

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