Coseismic versus interseismic ground deformations, fault rupture inversion and segmentation revealed by 2003 <i>Mw</i> 6.8 Chengkung earthquake in eastern Taiwan

Wu, Yih‐Min; Chen, Y. G.; Shin, Tzay Chyn; Kuo-Chen, Hao; Hou, Chin-Shyong; Hu, Jyr Ching; Chang, Chien Hsin; Wu, Chien-Fu; Teng, Ta‐Liang

doi:10.1029/2005gl024711

Cited by 66 publications

(102 citation statements)

References 17 publications

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“…As shown in Figure 7, a high P-wave velocity region is associated with the Philippine Sea plate. Because of the active collision between the continent and the island arc, most of the seismic activity in the Taiwan region, including many large earthquakes, occurs in this area (Wang, 1998) with primary thrust-type faulting (Kuochen et al, 2004;Wu, Chen, Shin, et al, 2006). However, because of the bending of the Philippine Sea plate (Kuochen et al, 2004), normal faulting is perceptible as well.…”

Section: Results: Focal Mechanisms Of Taiwan Earthquakesmentioning

confidence: 99%

Focal-Mechanism Determination in Taiwan by Genetic Algorithm

Wu¹,

Zhao²,

Chang³

et al. 2008

Bulletin of the Seismological Society of America

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We determined the focal-mechanism solutions for earthquakes with magnitude M L ≥ 4:0 that occurred in the Taiwan region between 1991 and 2005. Firstmotion polarities of P waves recorded at over 700 seismic stations in Taiwan were used. Because of the large number of events and stations involved, we implemented the genetic algorithm in a nonlinear global search for the focal-mechanism solutions. The algorithm was tuned and validated through synthetic tests. We finally determined the focal mechanisms of 1635 events with good qualities among 4188 earthquakes. Focal-mechanism solutions for a majority of the earthquakes display a dominant pattern of thrust-fault type reflecting the compressive stress field due to the plate collision. Normal-fault events occurred at intermediate depths in subduction zones, which is likely the result of the bending of the subducting slabs. Strike-slip faults are also found within the Eurasia plate around the Peikang Basement High and in collision zones near Ilan where the geometry of the colliding plates is complex. Our study provides a database of focal mechanisms for studying seismogenic structures and plate tectonics. This database can also be used by structural seismologists to compute synthetics for waveform tomography studies.

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Section: Results: Focal Mechanisms Of Taiwan Earthquakesmentioning

confidence: 99%

Focal-Mechanism Determination in Taiwan by Genetic Algorithm

Wu¹,

Zhao²,

Chang³

et al. 2008

Bulletin of the Seismological Society of America

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“…In the north portion there have been thrust-type and also a few normal and strike-slip earthquakes (Hsu 2001;Yu and Kuo 2001;Kuochen et al 2004). In contrast the southern portion of the LVF revealed a dominant thrust-type earthquake faulting mechanism with minor strike-slip faulting (Barrier and Angelier 1986;Chen and Rau 2002;Kuochen et al 2004;Wu et al 2006;Wu et al 2008). According to the 1991 -1999 GPS campaigned measurements, more than one-third of plate convergence of about 3 cm yr -1 is attributed to horizontal shortening across the LVF at the middle and southern part of the valley (Yu et al 1990;Lee and Angelier 1993;Yu and Kuo 2001).…”

Section: Geological Settingmentioning

confidence: 99%

Campaigned GPS on Present-Day Crustal Deformation in Northernmost Longitudinal Valley Preliminary Results, Hualien Taiwan

Chen¹,

Lee²,

Chen³

et al. 2014

Terr. Atmos. Ocean. Sci.

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The Longitudinal Valley in Eastern Taiwan sits at the collision suture between the Eurasian and Philippine Sea plates. Based on repeated GPS campaigned measurements from 25 stations six times in 2007 -2009, we characterize the surface deformation in the northernmost Longitudinal Valley where the Coastal Range of the Philippine Sea plate turns northward diving under the Eurasian plate producing two major active faults: the Milun fault and the Longitudinal Valley fault. We reconstructed a GPS velocity field and conducted strain analyses and elastic block modeling. Our results suggest a rapid clockwise rotation of 33° Myr -1 and an eastward tectonic escape in the small Hualien City block (HUAL) area of ~10 × 10 km, which is apparently detached from the regional rotating RYUK block defined by previous studies. We interpret it as being initiated locally by the northwest indentation of the Coastal Range, which pushed the HUAL block to move upward and eastward. According to our strain analyses, the HUAL block shows a significant internal elastic strain inside the Milun Tableland, the hanging wall of the Milun fault. No significant deformation was observed across the surface trace of the fault, indicating that the Milun fault is now probably locked in the near surface. The deformation in the footwall of the fault was accommodated by pure-shear strain with a major NNW-compression and a minor ENE-extension. The deformation in the hanging wall is characterized by simple-shear strain with ENE-extension in its northern part and little deformation in the southern part, separated by a little known NW-trending active fault zone (Dongmingyi fault), which needs further investigation.

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“…The southern part of the LVF shows listric fault geometry. A recent destructive earthquake along the southern LVF occurred in 2003, the Chishang earthquake (Mw 6.8) [Wu et al, 2006;Hu et al, 2007;Ching et al, 2007].…”

Section: Crustal Deformation Around the Lvfmentioning

confidence: 99%

Coseismic displacement and tectonic implication of 1951 Longitudinal Valley earthquake sequence, eastern Taiwan

Lee¹,

Chen²,

Rau³

et al. 2008

J. Geophys. Res.

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The Longitudinal Valley Fault (LVF) in eastern Taiwan is an extremely active fault with 3–4 cm of displacements consumed each year along its length. The fault forms the suture zone between the Philippine Sea and Eurasian plates as a result of an oblique arc continental collision. From 22 October to 5 December 1951, four earthquakes (Ms > 7) shook the LVF. We used triangulation (from 1917 to 1921 to 1976–1978) and interseismic GPS (from 1990 to 1995) data to estimate coseismic displacements of the 1951 earthquake sequences. Coseismic displacement progressively decreases from north to south and the azimuth changes from north to NE, then to a NW direction. According to the inverted faulting mechanism, the Longitudinal Valley fault can be separated into three segments. Both the northern and central segments have a high dip angle to the east, but the southern segment is of listric fault geometry. The northern segment exhibits dominantly left lateral strike‐slip faulting with reverse component, while the middle exhibits thrusting dominantly, and the southern segment exhibits thrusting with left‐lateral motion associated with a smaller coseismic displacement. In addition, this three‐segment deformation model can explain the pattern of recent crustal deformation along the LVF and Coastal Range.

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Coseismic versus interseismic ground deformations, fault rupture inversion and segmentation revealed by 2003 Mw 6.8 Chengkung earthquake in eastern Taiwan

Cited by 66 publications

References 17 publications

Focal-Mechanism Determination in Taiwan by Genetic Algorithm

Focal-Mechanism Determination in Taiwan by Genetic Algorithm

Campaigned GPS on Present-Day Crustal Deformation in Northernmost Longitudinal Valley Preliminary Results, Hualien Taiwan

Coseismic displacement and tectonic implication of 1951 Longitudinal Valley earthquake sequence, eastern Taiwan

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