TY - JOUR
T1 - Characterization of slow slip rate faults in humid areas
T2 - Cimandiri fault zone, Indonesia
AU - Marliyani, G. I.
AU - Arrowsmith, Ramon
AU - Whipple, Kelin
N1 - Publisher Copyright:
©2016. American Geophysical Union. All Rights Reserved.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2016/12/1
Y1 - 2016/12/1
N2 - In areas where regional tectonic strain is accommodated by broad zones of short and low slip rate faults, geomorphic and paleoseismic characterization of faults is difficult because of poor surface expression and long earthquake recurrence intervals. In humid areas, faults can be buried by thick sediments or soils; their geomorphic expression subdued and sometimes undetectable until the next earthquake. In Java, active faults are diffused, and their characterization is challenging. Among them is the ENE striking Cimandiri fault zone. Cumulative displacement produces prominent ENE oriented ranges with the southeast side moving relatively upward and to the northeast. The fault zone is expressed in the bedrock by numerous NE, west, and NW trending thrust- and strike-slip faults and folds. However, it is unclear which of these structures are active. We performed a morphometric analysis of the fault zone using 30 m resolution Shuttle Radar Topography Mission digital elevation model. We constructed longitudinal profiles of 601 bedrock rivers along the upthrown ranges along the fault zone, calculated the normalized channel steepness index, identified knickpoints and use their distribution to infer relative magnitudes of rock uplift and locate boundaries that may indicate active fault traces. We compare the rock uplift distribution to surface displacement predicted by elastic dislocation model to determine the plausible fault kinematics. The active Cimandiri fault zone consists of six segments with predominant sense of reverse motion. Our analysis reveals considerable geometric complexity, strongly suggesting segmentation of the fault, and thus smaller maximum earthquakes, consistent with the limited historical record of upper plate earthquakes in Java.
AB - In areas where regional tectonic strain is accommodated by broad zones of short and low slip rate faults, geomorphic and paleoseismic characterization of faults is difficult because of poor surface expression and long earthquake recurrence intervals. In humid areas, faults can be buried by thick sediments or soils; their geomorphic expression subdued and sometimes undetectable until the next earthquake. In Java, active faults are diffused, and their characterization is challenging. Among them is the ENE striking Cimandiri fault zone. Cumulative displacement produces prominent ENE oriented ranges with the southeast side moving relatively upward and to the northeast. The fault zone is expressed in the bedrock by numerous NE, west, and NW trending thrust- and strike-slip faults and folds. However, it is unclear which of these structures are active. We performed a morphometric analysis of the fault zone using 30 m resolution Shuttle Radar Topography Mission digital elevation model. We constructed longitudinal profiles of 601 bedrock rivers along the upthrown ranges along the fault zone, calculated the normalized channel steepness index, identified knickpoints and use their distribution to infer relative magnitudes of rock uplift and locate boundaries that may indicate active fault traces. We compare the rock uplift distribution to surface displacement predicted by elastic dislocation model to determine the plausible fault kinematics. The active Cimandiri fault zone consists of six segments with predominant sense of reverse motion. Our analysis reveals considerable geometric complexity, strongly suggesting segmentation of the fault, and thus smaller maximum earthquakes, consistent with the limited historical record of upper plate earthquakes in Java.
KW - Cimandiri fault
KW - Java active fault
KW - active fault study
KW - channel steepness
KW - knickpoints
KW - slow slip rate faults
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U2 - 10.1002/2016JF003846
DO - 10.1002/2016JF003846
M3 - Article
AN - SCOPUS:85006421103
SN - 2169-9003
VL - 121
SP - 2287
EP - 2308
JO - Journal of Geophysical Research: Earth Surface
JF - Journal of Geophysical Research: Earth Surface
IS - 12
ER -