Fault mechanism and recurrence time of major earthquakes in southern Kanto district, Japan, as deduced from coastal terrace data

“…The 1923 (Taisho) and 1703 (Genroku) Kanto earthquakes characterize the first and second types, respectively. Both of them are megathrust events at the same plate interface, but their source regions seem to be somewhat different because of significant difference in coseismic displacement patterns (e.g., Matsuda et al 1978). The fault slip distribution of the 1923 Taisho event has been estimated from geodetic (triangulation and leveling) data by many researchers (e.g., Ando 1971;Matsu'ura et al 1980Matsu'ura et al , 2007Kobayashi and Koketsu 2005).…”

Section: Introductionmentioning

confidence: 99%

“…According to Matsuda et al (1978), two different types of large interplate earthquakes have repeatedly occurred in the southern Kanto region. The 1923 (Taisho) and 1703 (Genroku) Kanto earthquakes characterize the first and second types, respectively.…”

Section: Introductionmentioning

confidence: 99%

The source model and recurrence interval of Genroku-type Kanto earthquakes estimated from paleo-shoreline data

et al. 2016

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In the southern Kanto region of Japan, where the Philippine Sea plate is descending at the Sagami trough, two different types of large interplate earthquakes have occurred repeatedly. The 1923 (Taisho) and 1703 (Genroku) Kanto earthquakes characterize the first and second types, respectively. A reliable source model has been obtained for the 1923 event from seismological and geodetical data, but not for the 1703 event because we have only historical records and paleo-shoreline data about it. We developed an inversion method to estimate fault slip distribution of interplate repeating earthquakes from paleo-shoreline data on the idea of crustal deformation cycles associated with subduction-zone earthquakes. By applying the inversion method to the present heights of the Genroku and Holocene marine terraces developed along the coasts of the southern Boso and Miura peninsulas, we estimated the fault slip distribution of the 1703 Genroku earthquake as follows. The source region extends along the Sagami trough from the Miura peninsula to the offing of the southern Boso peninsula, which covers the southern two thirds of the source region of the 1923 Kanto earthquake. The coseismic slip takes the maximum of 20 m at the southern tip of the Boso peninsula, and the moment magnitude (Mw) is calculated as 8.2. From the interseismic slip-deficit rates at the plate interface obtained by GPS data inversion, assuming that the total slip deficit is compensated by coseismic slip, we can roughly estimate the average recurrence interval as 350 years for large interplate events of any type and 1400 years for the Genroku-type events.

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“…1) (Hatori et al 1973;Satake et al 2008;Namegaya et al 2011). Thus, the source area of the 1703 earthquake is believed to include both the region between the Sagami Bay and the southern Boso Peninsula as well as the offshore area along the Sagami Trough (e.g., Matsuda et al 1978;Satake et al 2008;Namegaya et al 2011).…”

Section: Introductionmentioning

confidence: 99%

“…During the 1703 and 1923 events, crustal deformations along the coastline of the southern Boso Peninsula appeared as marine terraces or uplifted littoral bio-constructions (Matsuda et al 1978;Shishikura 2014). Studies have proposed fault models for the 1703 earthquake using inversion analyses of the observed heights of the crustal deformations (e.g., Namegaya et al 2011;Cabinet Office 2013;Sato et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Source model of the 1703 Genroku Kanto earthquake tsunami based on historical documents and numerical simulations: modeling of an offshore fault along the Sagami Trough

Yanagisawa

Goto

2017

Earth Planets Space

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The 1703 Genroku Kanto earthquake and the resulting tsunami caused catastrophic damage in the Kanto region of Japan. Previous modeling of the 1703 earthquake applied inversion analyses of the observed terrestrial crustal deformations along the coast of the southern Boso Peninsula and revealed that the tsunami was generated along the Sagami Trough. Although these models readily explained the observed crustal deformation, they were unable to model an offshore fault along the Sagami Trough because of difficulties related to the distance of the offshore fault from the shoreline. In addition, information regarding the terrestrial crustal deformation is insufficient to constrain such inverted models. To model an offshore fault and investigate the triggering of large tsunamis off the Pacific coast of the Boso Peninsula, we studied historical documents related to the 1703 tsunami from Choshi City. Based on these historical documents, we estimated tsunami heights of ≥5.9, 11.4-11.7, ≥7.7, 10.8 and ≥4.8 m for the Choshi City regions of Isejiga-ura, Kobatake-ike, Nagasaki, Tokawa and Na'arai, respectively. Although previous studies assumed that the tsunami heights ranged from 3.0 to 4.0 m in Choshi City, we revealed that the tsunami reached heights exceeded 11 m in the city. We further studied the fault model of the 1703 Genroku Kanto earthquake numerically using the newly obtained tsunami height data. Consequently, we determined that the source of the 1703 earthquake was a 120-km-long offshore fault along the Sagami Trough, which is in close proximity to the Japan Trench. Our results suggest that earthquake energies resulting in magnitudes greater than Mw 8.32 along the entire length of the Sagami Trough could have been released during the 1703 Genroku Kanto earthquake.

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Fault mechanism and recurrence time of major earthquakes in southern Kanto district, Japan, as deduced from coastal terrace data

Cited by 220 publications

References 0 publications

Progress in Paleoseismology in Japan during the 1990s.

Progress in Paleoseismology in Japan during the 1990s.

The source model and recurrence interval of Genroku-type Kanto earthquakes estimated from paleo-shoreline data

Source model of the 1703 Genroku Kanto earthquake tsunami based on historical documents and numerical simulations: modeling of an offshore fault along the Sagami Trough

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