Transition from oblique subduction to collision: Earthquakes in the southernmost Ryukyu arc‐Taiwan region

Kao, Honn; Shen, Sern-su Jack; Fong, Kuo

doi:10.1029/97jb03510

Cited by 153 publications

(186 citation statements)

References 86 publications

(34 reference statements)

Supporting

Mentioning

164

Contrasting

Order By: Relevance

“…However, as we mentioned in previous sections, strike-slip and normalfault mechanisms also occur due to the plate collision. At depths between 50 and 90 km, there is a simple down-dip extensional regime, along the maximum tensile axis in the down-dip direction of the plunging slab (Kao and Chen, 1991;Kao, Shen, and Ma, 1998;Kao and Rau, 1999). At the depth of about 80 km, the average dip of the slab changes slightly from 40°-50°to a steeper dip of about 60°.…”

Section: Results: Focal Mechanisms Of Taiwan Earthquakesmentioning

confidence: 99%

See 1 more Smart Citation

Focal-Mechanism Determination in Taiwan by Genetic Algorithm

Wu¹,

Zhao²,

Chang³

et al. 2008

Bulletin of the Seismological Society of America

View full text Add to dashboard Cite

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.

show abstract

Section: Results: Focal Mechanisms Of Taiwan Earthquakesmentioning

confidence: 99%

“…Many studies based on limited focal mechanisms have been conducted in the past in Taiwan tectonics (Kao, Jian, et al, 1998;Kao, Shen, and Ma, 1998;Kao and Rau, 1999;Chou et al, 2006). Focal mechanisms determined in this study provide an alternative database for the study of subduction systems.…”

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

View full text Add to dashboard Cite

show abstract

“…The study area, where Hualien City is located, is also at the transition zone of plate configuration flipping where the Philippine Sea plate turns from overriding the Eurasian plate in the south to subducting to it in the north (Suppe 1984;Burbank and Anderson 2001;Lallemand et al 2001;Malavieille et al 2002). According to previous seismological analyses, to the north of Hualien, the present shallow crustal deformation from Ilan to Hualien is accommodated by abundant faulting with a rather complex pattern, a mixture of normal faulting, thrust faulting and strike-slip faulting (Kao et al 1998;Rau et al 2008;Wu et al 2009). In contrast, to the south of Hualian along the western side of the Coastal Range, both the geodetic and seismological data show predominantly thrust-style deformation concentrated along the major geological mapped fault, the LVF, with a minor left-lateral strike-slip component (Yu and Lee 1986;Lee and Angelier 1993;Lu et al 1995;Yu et al 1997;Kao and Jian 2001;Yu and Kuo 2001;Rau et al 2008;Angelier et al 2009).…”

Section: Introductionmentioning

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.

View full text Add to dashboard Cite

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.

show abstract

“…Previous field mapping results of slate/schist outcrop results south of Suao suggested different ductile deformation stages (Yeh 1998) as the expectations of previous results (Suppe 1984;Kao et al 1998;Shyu et al 2005b). Two ductile deformation stages were clearly identified based on field mapping and microscopic examination in the Suao highway slate belt (Yeh 1998).…”

Section: Field Observations Of Ductile Deformationmentioning

confidence: 55%

“…Based on seismological observations, Kao et al (1998) suggests that this region is located where an interaction exists between the extension of the opening of OT and the compression of the PSP oblique collision. Generally, normal faulting in this region would be consistent with the opening and extension of the OT (e.g., Wang et al 2000;Shyu et al 2005b;Wu et al 2008a).…”

Section: Introductionmentioning

confidence: 99%

Tectonic Implication of the 5th March 2005, Doublet Earthquake in Ilan, Taiwan

Yeh¹,

Ôta

et al. 2016

Terr. Atmos. Ocean. Sci.

View full text Add to dashboard Cite

The 5 th March 2005 earthquake doublet focal mechanism was determined as strike-slip faulting from Harvard and BATS moment tensor inversion. However, based on first motion polarities, the first shock has a normal focal mechanism (Wu et al. 2008a). This discrepancy has caused a debate over the focal mechanism solution because different focal mechanisms have different tectonic implications. Based on the dislocation determination from Global Position System (GPS) measurements, we find this event includes both tensile and strike-slip components. This finding illustrates the reason for the differences in the determined focal mechanisms using two different types of seismic data and analyzing methods. Field mapping and microstructure examination results indicate that the ductile deformation around the study area was characterized by the evolution from transpression to transtension with a predominant strike-slip component, but present-day active structures may be dominated by normal faulting. Thus, the active tensile slip result determined from dislocation modeling strongly suggests that the back arc extension of the Okinawa trough influences the stress state in this region, and changes the major transtension from strike-slip faulting to normal faulting.

show abstract

Transition from oblique subduction to collision: Earthquakes in the southernmost Ryukyu arc‐Taiwan region

Cited by 153 publications

References 86 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

Tectonic Implication of the 5th March 2005, Doublet Earthquake in Ilan, Taiwan

Contact Info

Product

Resources

About