Abstract The seismicity in the Korean Peninsula has increased since 2011 M w 9.0 Tohoku‐Oki megathrust earthquake. Two strike‐slip earthquakes with magnitudes of L 5.1 and 5.8 occurred southeastern on 12 September 2016. two events within 48 min. earthquake was largest event 1978 when national seismic monitoring began. Both produced strong high‐frequency ground motions. More than 500 aftershocks local greater or equal to 1.5 followed for 2 months. An unreported subsurface fault a dip 65° east...

Abstract The distance-dependent coseismic and postseismic displacements produced by the 2011 M W 9.0 Tohoku-Oki megathrust earthquake caused medium weakening stress perturbation in crust around Korean Peninsula, increasing seismicity with successive L 5-level earthquakes at outskirts of high regions. average occurrence rate prior to was 0.15 yr −1 (0.05–0.35 a 95% confidence level), has increased 0.71 (0.23–1.67 level) since earthquake. 2016 midcrustal additionally changed field adjacent...

The crustally guided shear wave, Lg , is typically the most prominent phase of a nuclear explosion at regional distance. This analyzed often to discriminate from natural earthquake. In addition, allows us determine size detonation. A test in North Korea was conducted on 9 October 2006. epicenter located close eastern shore Korean Peninsula, resulting raypaths that vary significantly according azimuths. particular, rays radiated southern direction experience lateral variation crustal...

Research Article| October 01, 2013 Probabilistic Analysis of the Korean Historical Earthquake Records Soung Eil Houng; Houng Yonsei University, Department Earth System Sciences, 50 Yonsei‐ro, Seodaemun‐gu, Seoul 120‐749, South Koreatkhong@yonsei.ac.kr Search for other works by this author on: GSW Google Scholar Tae‐Kyung Hong Author and Article Information Publisher: Seismological Society America First Online: 14 Jul 2017 Online ISSN: 1943-3573 Print 0037-1106 Bulletin (2013) 103 (5):...

The rise in seismic activity since the Mw 5.8 Gyeongju earthquake 2016 has prompted a detailed study of subsurface fault systems South Korea. Given potential for moderate to cause significant damage and loss lives densely populated Seoul metropolitan area, investigating this region is an urgent task. We jointly invert S-wave travel times Rayleigh-wave phase group velocities identify seismogenic faults taking advantage complementary resolutions three different datasets. obtained 3,837...

The 1 January 2024 Mw7.5 Noto Peninsula earthquake generated a tsunami that spread across the East Sea (Sea of Japan). We investigate effect on coast in regional distances using tsunami-induced seismic wavetrains recorded by borehole broadband seismometers Korean Peninsula. are observed stations near coast. consistent with records tide gauges. shared features waveforms and spectral contents between waves signals suggest energy origins same. coastal loading induces ground tilting around...

Intraplate seismicity has been poorly understood relative to interplate seismicity, which may be partly due low and long earthquake recurrence intervals ambiguity in the responsible structures. Locally clustered earthquakes provide essential information on nature of intraplate such as earthquake-spawning mechanisms, source properties, seismogenic depths structures, stress accumulation release patterns, rupture processes, potential seismic hazards. The Korean Peninsula, located a stable...

This study investigates the three-dimensional seismic velocity and attenuation structures of eastern Sino-Korean Craton through analysis an extensive dataset from China South Korea. The comprises 87,260 earthquakes recorded by 680 Chinese stations since 2008 5,400 483 Korean 2017. methodological framework includes 1D model inversion, event relocation, manual picking Pg, Pn, Sg, Sn arrivals, assisted a machine-learning-based approach. A modified ray-tracing technique, optimized for tracking...

Abstract The crustally-guided shear wave, Lg , is typically the strongest phase at regional distances. phases are analyzed often for estimation of magnitudes events. variation in regions with both continental and oceanic environments has been rarely investigated. We investigate attenuation a plate-margin area around Korea Japan that encompassed by seas oceans. mean quality factor 1 Hz ( Q 0 ) 498. geometrical-spreading exponent term estimated as 0.75. These observations characterize study...

ABSTRACT The Korean Peninsula is located in a stable intraplate region with low-seismicity rates and long recurrence intervals of major earthquakes. Recent moderate-size earthquakes demonstrate possible occurrence seismic damages the Peninsula. A probabilistic hazard analysis based on instrumental historical seismicity applied for Three seismotectonic province models are used area sources. Seven ground-motion prediction equations calibrated bedrock condition considered. Fault source not due...

Abstract A recent dense deployment of seismic stations in South Korea and Japan allows regional imaging the far-east Asian region that experienced continental collisions riftings. We perform based on a mantle-lid P -wave ( Pn ) travel-time tomography to exploit tectonic imprints lithosphere. The average velocity is estimated be 7.95±0.03 km/sec. inverted velocities illuminate structures. High ∼8.15 km/sec are observed Precambrian massif regions, while low ∼7.8 associated with fold belt...

After the devastating Tohoku-Oki earthquake (Mw 9.0, 2011) in Japan, Korean Peninsula has experienced a higher number of large, plus Mw 5.0, earthquakes than recorded preceding half century modern monitoring. In addition, seismicity dramatically increased along with seismic waves arriving later prior to 2011 earthquake, suggesting that crust notably been perturbed. South Korea is densely populated, hence knowledge about active faults and mechanisms great relevance for public safety risk...

Abstract The 9 October 2006 underground nuclear explosion (UNE) test in North Korea was well monitored by dense regional seismic stations South Korea, Japan, and China. This observation allows extensive investigation of the source properties UNE. moment for isotropically radiated energy from UNE is estimated to be 2.92×10 14 N m. Source spectra major phases are studied inverting apparent moments, corner frequencies, overshoot parameters, attenuation factors, frequency power-dependence...

Abstract Quaternary faults run across the Seoul metropolitan area that is highest population region in Korean Peninsula. Active fault identification and seismic hazard potential assessment are crucial for public safety. Densely deployed permanent temporal stations enabled us to detect micro small earthquakes, allowing identify earthquake‐spawning area. The source parameters of 455 earthquakes 2004–2020 refined. Gutenberg‐Richter b value 0.94. Dominant focal depths 4–15 km. mechanism...

ABSTRACT Earthquake records in the historical literature provide valuable information on seismic hazard potentials for long recurrence times. The Seoul metropolitan area is center of economy and infrastructure South Korea. Six major earthquakes that occurred around during Joseon dynasty 1392–1910 are analyzed using a probabilistic joint inversion method based damage earthquake-felt reports. yields sets event locations magnitudes with probabilities. validated synthetic instrumentally observed...

Abstract Major earthquakes in continental regions may cause significant damage. Preexisting fault system across megacity receives high attention for possible seismic damages. Earthquake occurrence mechanism is important to assess the geohazard potentials. Continental‐scale Quaternary developed Seoul metropolitan area where population largest Korean Peninsula. Historical seismic‐damage records suggest potential hazards area. We investigate motions and spatial distribution of using a...

The passage of seismic waves through highly heterogeneous media leads to significant scattering energy and an apparent attenuation signals emerging from the zone. size this depends on correlation properties medium, rates P- S-wave velocities, frequency content incident waves. An estimate effect can be obtained using single theory (first-order Born approximation) for path deviations beyond a minimum angle; smaller require consideration multiple or representation in terms travel-time...

Abstract The Conrad discontinuity, a boundary between the upper and lower crusts, has long been identified in many continental crusts. influence of discontinuity on seismic hazards, however, rarely known. Strong regional phases corresponding to waves refracted from are observed Korean Peninsula. These show strong amplitudes 2–4 times larger than those direct waves. observation is confirmed by numerical modeling waveforms. observations not only support existence Peninsula but also suggest...

Abstract We investigate the upper‐crustal seismic velocity structure in Seoul metropolitan area, where about 20 million people live. The Chugaryeong fault zone (CFZ) is placed this but hazard potential remains unclear. conducted ambient noise tomography to illuminate high‐resolution area. analyzed continuous vertical records for ∼5 months from a dense array with 77 broadband stations. Group dispersion curves and tomographic maps were extracted between 0.5 10 s periods. inverted 3‐D group...

ABSTRACT The crustal structure and Quaternary fault zone in the Seoul metropolitan area are investigated using a joint inversion that combines receiver functions with surface wave dispersion based on seismic data from densely deployed arrays. uncertainty inverted models is examined through set of synthetic experiments. Synthetic tests comparisons other methods verify observed features. Moho depths range between 28.7 32.8 km relatively shallow central area. VP/VS ratio varies 1.67 1.85. A...

A South Korean naval vessel sank on 26 March 2010. seismic event with magnitude (ML) of 1.5 was observed at the time vessel-sinking. Seismic waveforms were collected from three local stations. The origin is refined based P and S arrival times calculated location are close to reported vessel-sinking time, suggesting that associated amplitudes waves comparable those waves. coupled acoustic observed, providing additional constraints epicentral distance source type. have a dominant frequency ∼32...