Comparative Analysis of Structural Damage Potentials Observed in the 9.12 Gyeongju and 11.15 Pohang Earthquakes

이철호,; 김성용,; 박지훈,; 김동관,; 김태진,; 박경훈,

doi:10.5000/eesk.2018.22.3.175

Cited by 9 publications

(3 citation statements)

References 4 publications

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“…Then, about a year later, a magnitude 5.4 earthquake occurred in Pohang, close to Gyeongju, and this earthquake is known to have been triggered by water injection into a borehole for geothermal power generation (Kim et al 2018;Lim et al 2020). These two earthquakes were accompanied by a number of foreshocks and aftershocks (Kim and Lee 2019) and caused considerable damage to the surrounding area (Eem et al 2018;Ghim et al 2018;Jin et al 2019;Lee et al 2018). As a result, national and social interest in earthquakes have increased, and research on seismic hazards has become active.…”

Section: Introductionmentioning

confidence: 99%

Comparison of earthquake catalogs declustered from three different methods in the Korean Peninsula

Kim¹

2023

Preprint

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The earthquake catalog includes both dependent earthquakes, which are spatio-temporally related to each other, and independent or background earthquakes. In order to predict the long-term seismicity or perform seismic hazard research, the dependent earthquakes must be removed to generate a declustered earthquake catalog. However, several declustering methods have been proposed, and the evaluation of seismic hazard may vary depending on the selected declustering method. In the present study, the catalog of earthquakes that were observed between 2016 and 2021 in and around the Korean peninsula is declustered using the methods of Gardner and Knopoff (1974), Reasenberg (1985), and Zhuang et al. (2002), and the resultant catalogs are compared. The values of the seismicity parameters (a and b) in the Gutenberg-Richter relationship are estimated from the declustered catalogs, and are seen to vary depending on the declustering method, thereby affecting the results of long-term earthquake prediction or seismic hazard analysis. In addition, three approaches are used to test whether the original (raw) and declustered catalogs follow the Poisson process or not. The minimum magnitude (Mp) above which the null hypothesis of the Poisson process cannot be rejected in the earthquake catalog is shown to range from 1.6 to 2.2 depending on the declustered catalog and the test method used. Further, the Mp obtained herein shows a large value compared to the completeness magnitude estimated in the present study. A comparison of the curves representing the cumulative number of background earthquakes versus the elapsed time for the various declustered catalogs shows that the method of Zhuang et al. (2002) gives the closest agreement with the real background seismicity curve.

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Section: Introductionmentioning

confidence: 99%

Comparison of earthquake catalogs declustered from three different methods in the Korean Peninsula

Kim¹

2023

Preprint

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“…These two earthquakes were accompanied by many foreshocks and aftershocks [Kim and Lee, 2019], causing considerable damage to the surrounding area [Eem et al, 2018;Ghim et al, 2018;Lee et al, 2018;Jin et al, 2020].…”

Section: Introductionmentioning

confidence: 99%

Comparison of earthquake catalogs for the Korean Peninsula declustered using three different methods

Kim

2023

Annals of Geophysics

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Earthquake catalogs include dependent earthquakes, which are spatiotemporally related, and independent or background earthquakes. In order to predict long-term seismicity or conduct a seismic hazard assessment, the dependent earthquakes must be removed to generate a declustered earthquake catalog. Several declustering methods have been proposed to date; however, the result of seismic hazard assessment may vary depending on which declustering methods are selected. In the present study, the catalog of earthquakes that were observed between 2016 and 2021 in and around the Korean Peninsula is declustered using the methods proposed by Gardner and Knopoff [1974], Reasenberg [1985], and Zhuang et al. [2002], and the resultant catalogs are compared. The seismicity parameters (a- and b-values) in the Gutenberg-Richter relationship are found to vary among the three declustered catalogs, thus affecting long-term earthquake predictions and seismic hazard assessment. The raw (original) and three declustered catalogs are also tested to see whether they follow the Poisson process. The minimum magnitude ( ) above which the null hypothesis of the Poisson process cannot be rejected in the earthquake catalogs ranges from 1.6 to 2.2, depending on the declustered catalog. Further, the obtained herein shows a large value compared to the completeness magnitude estimated in the present study. Comparing the curves representing the cumulative number of background earthquakes against the elapsed time for the declustered catalogs shows that the method by Zhuang et al. [2002] produces the result in the closest agreement with the real background seismicity curve.

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“…After the 2011 Tohoku earthquake occurred off the Pacific coast of Japan, earthquakes have also been observed in the southeastern Korean Peninsula and the southwestern part of the Ulleung Basin 1-5 . More recently, the Gyeongju and Pohang earthquakes in Korea, which occurred on Sep. 12, 2016 and Nov. 15, 2017, respectively, caused damage to the value of more than 100 billion won 1,2,4,6,7 . In May 1983 and Jul.…”

mentioning

confidence: 99%

Gravity and magnetic anomalies of earthquake-prone areas in the southwestern Ulleung basin margin, East Sea (Sea of Japan)

Kim

Choi

et al. 2022

Sci Rep

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Submarine earthquakes have increased in the southwestern Ulleung Basin adjacent to the Korean Peninsula. This study analyzed the gravitational and magnetic properties of the three earthquake-prone areas (Hupo Bank and offshore regions near Pohang and Ulsan) in the basin. The basin was affected by tensile and compressive stresses during the formation of the East Sea. The southern Hupo Bank and the Pohang offshore exhibited high gravity anomalies and strong magnetic anomalies. Hupo Bank was separated from the peninsula and earthquakes in this region have been influenced by crustal fractures that facilitated igneous activities during the formation of the basin. Dense volcanic rocks and seaward dipping reflectors along the Pohang coast and continental slope suggest magmatic activities during the formation of the East Sea. Comparatively, the Ulsan offshore, with a thick sedimentary layer, exhibited a slightly higher gravity anomaly than the surrounding area, but no significant differences in the magnetic anomaly. Sequential tensile and compressive stresses related to the creation of the basin produced complex tectonic structures in this region. The magnetic tilt derivative results suggest that earthquakes were located near magnetic source boundaries. The results show that it is important to monitor earthquake-prone areas with gravity and magnetic anomalies.

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Comparative Analysis of Structural Damage Potentials Observed in the 9.12 Gyeongju and 11.15 Pohang Earthquakes

Cited by 9 publications

References 4 publications

Comparison of earthquake catalogs declustered from three different methods in the Korean Peninsula

Comparison of earthquake catalogs declustered from three different methods in the Korean Peninsula

Comparison of earthquake catalogs for the Korean Peninsula declustered using three different methods

Gravity and magnetic anomalies of earthquake-prone areas in the southwestern Ulleung basin margin, East Sea (Sea of Japan)

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