The Wangsan Fault: One of the most ‘active’ faults in South Korea?

Ree, Jin-Han; Kwon, SangJoo

doi:10.1007/bf02910581

Cited by 16 publications

(8 citation statements)

References 11 publications

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“…On the other hand, more than twenty Quaternary faults have been reported adjacent to the NNE-striking, strike-slip Yangsan Fault in southeastern Korea since the early 1990's (see Fig. 1; Kyung 1997;Okada et al 1998;Kyung & Chang 2001;Cheong et al 2003;Ree et al 2003;Kim et al 2004b;Ree & Kwon 2005;Park et al 2006). Our results can be compared with those from the studies of the Quaternary faults.…”

Section: Discussionmentioning

confidence: 56%

“…To evaluate the orientation of the regional stress responsible for the earthquake events, a fault-slip analysis (or fault-slip data inversion analysis; Angelier 1994) was performed using nodal planes and slip vectors determined from the focal mechanism solutions. From the two nodal planes of each earthquake event, the one striking NNW to NE was preferentially selected for the fault-slip analysis since all of the Quaternary faults reported so far in South Korea show these orientations (Kyung 1997;Okada et al 1998;Kyung & Chang 2001;Cheong et al 2003;Ree et al 2003;Kim et al 2004b;Ree & Kwon 2005;Park et al 2006). For the earthquake events of which two nodal planes have other orientation than NNW to NE Figure 6.…”

Section: R E S U Lt Smentioning

confidence: 99%

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Focal mechanisms of recent earthquakes in the Southern Korean Peninsula

Park¹,

Kim

Chung

et al. 2007

Geophysical Journal International

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S U M M A R YWe evaluate the stress field in and around the southern Korean Peninsula with focal mechanism solutions, using the data collected from 71 earthquakes (M L = 1.9-5.2) between 1999 and 2004. For this, the hypocentres were relocated and well-constrained fault plane solutions were obtained from the data set of 1270 clear P-wave polarities and 46 SH/P amplitude ratios. The focal mechanism solutions indicate that the prevailing faulting types in South Korea are strike-slip-dominant-oblique-slip faultings with minor reverse-slip component. The maximum principal stresses (σ 1 ) estimated from fault-slip inversion analysis of the focal mechanism solutions show a similar orientation with E-W trend (269 • -275 • ) and low-angle plunge (10 • -25 • ) for all tectonic provinces in South Korea, consistent with the E-W trending maximum horizontal stress (σ Hmax ) of the Amurian microplate reported from in situ stress measurements and earthquake focal mechanisms. The directions of the intermediate (σ 2 ) and minimum (σ 3 ) principal stresses of the Gyeongsang Basin are, however, about 90 deg off from those of the other tectonic provinces on a common σ 2 -σ 3 plane, suggesting a permutation of σ 2 and σ 3 . Our results incorporated with those from the kinematic studies of the Quaternary faults imply that NNW-to NE-striking faults (dextral strike-slip or oblique-slip with a reverse-slip component) are highly likely to generate earthquakes in South Korea.

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Section: Discussionmentioning

confidence: 56%

Section: R E S U Lt Smentioning

confidence: 99%

Focal mechanisms of recent earthquakes in the Southern Korean Peninsula

Park¹,

Kim

Chung

et al. 2007

Geophysical Journal International

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“…In both BM5.8 and AM5.8, there is only one common point of the high value distributions in both periods. For BM5.8, high values mainly distribute along the UF for layers 1-4, including subsidiary faults in the coastal region where past motion has also been identified (Lee and Schwarcz 2001;Ree and Kwon 2005;Kim et al 2011). However, bluish high values are relatively rare along the YF as compared to other faults.…”

Section: Resultsmentioning

confidence: 88%

“…The region hosts two major faults: the Yangsan fault (YF), and the Ulsan fault (UF). With approximate lengths of 170 and 50 km, respectively (Figure 1), they may have been involved in past hazardous events (Lee and Na 1983;Lee and Schwarcz 2001;Kyung 2003;Ree and Kwon 2005;Chang 2011).…”

Section: Introductionmentioning

confidence: 99%

Seismic Scatter Associated with Earthquakes that Ended a Quiescent Period in Southeastern Korea

Iqbal

Chung

Nam

2020

Preprint

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Two recent hazardous earthquakes ( M 5.8 and 5.5) in southeastern Korea were the largest instrumentally recorded inland events after an abnormally long, seismically quiet, period. In this study, we used coda envelope tomography to observe the heterogeneities related to active faults, which can, in turn, help mitigate seismic hazard in the area. However, this tomography was not able to detect faults in the intraplate region. By separating the periods before and after the M 5.8 earthquake, we analyzed 225 and 204 seismograms obtained from 127 and 86 events, respectively. Both periods showed time-varying heterogeneity correlated with fault activity. Adding 446 seismograms from 235 aftershocks of the two events to the analysis showed us a heterogenous structure that closely correlated to the active faults where the recent earthquakes originated.

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“…Uplift or subsidence movement changes the topographic gradient, which could change the sedimentation pattern (Burnett & Schumm, ; Ouchi, 1985; Smith, ; Smith & Putnam, ). Considering that the study area belongs to the southeastern part of Korea where a number of Quaternary faults have been documented (Kee et al, ; Y. Kim et al, ; Kyung, ; Kyung et al, ; Lee, Ryoo, & Chwae, ; Ree et al, ; Ree & Kwon, ; Ryoo, Lee, & Chwae, ), the change of sedimentation process in this area could be considered as a result of tectonic activity. Although it is difficult to conclude that the environmental change from Stage 1 to Stage 2 is related to tectonic activity, the environmental change from Stage 2 to Stage 3, where the discontinuity surface develops, suggests the possibility that the large amount of coarser gravels were supplied under tectonic activity accompanied by the climatic shift from humid to arid conditions.…”

Section: Discussionmentioning

confidence: 99%

A discontinuity in the late Pleistocene alluvial deposits, Hwacheon‐ri, Gyeongju, Korea: Occurrences and paleoenvironmental implication

et al. 2018

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A sedimentary discontinuity is present in the late Pleistocene alluvial deposits exposed along the cliff in stream side, Gyeongju, Korea. Sedimentological study, Optically Stimulated Luminescence (OSL) age dating, and X‐ray diffraction (XRD), and X‐ray fluorescence spectrometer (XRF) analyses were conducted in order to interpret the origin of the discontinuity surface. Based on the sedimentological study, these deposits can be divided into three distinct stages, in ascending order: (Stage 1) development of a braided stream flowing from south to north and deposition by debris flows from the mountain aside the stream during and/or after deposition of the braided stream; (Stage 2) deposition by intermittent events during a state of stagnation after the abandonment or migration of the previously existed braided stream; and (Stage 3) deposition of gravels from debris flows from the mountain aside the stream. Hornfelsic gravels are common in Stage 1, whereas andesitic gravels are predominant in Stage 3, suggesting the provenance change from Stage 1 to Stage 3. The discontinuity surface is laterally extensive and marked by a distinct carbonaceous dark grey horizon between Stage 2 and Stage 3. It is characteristic that rootlets mineralized by vivianite are present, and iron‐oxide crusts are cutting across irregularly below the discontinuity surface. It is thus interpreted that the shift of depositional environment from an alluvial plain (Stage 2) (125 ka) to an alluvial fan (Stage 3) (94–55 ka) was an alluvial response to sea level change from the interglacial to the glacial. The development of iron‐oxide crusts and diagenetic vivianite in the discontinuity surface suggests humid condition persisted during the paleoclimatic shift from the last interglacial to the last glacial stages.

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The Wangsan Fault: One of the most ‘active’ faults in South Korea?

Cited by 16 publications

References 11 publications

Focal mechanisms of recent earthquakes in the Southern Korean Peninsula

Focal mechanisms of recent earthquakes in the Southern Korean Peninsula

Seismic Scatter Associated with Earthquakes that Ended a Quiescent Period in Southeastern Korea

A discontinuity in the late Pleistocene alluvial deposits, Hwacheon‐ri, Gyeongju, Korea: Occurrences and paleoenvironmental implication

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