A bump on the upper surface of the Philippine Sea plate beneath the Boso Peninsula, Japan inferred from seismic reflection surveys: A possible asperity of the 1703 Genroku earthquake

Tsumura, Noriko; Komada, Nozomi; Sano, Junpei; Kikuchi, Shinsuke; Yamamoto, S.; Ito, Tomohiro; Sato, Toshinori; Miyauchi, Takashi; Kawamura, T.; Shishikura, Masanobu; Abe, Shintaro; Satō, Hiroshi; Kawanaka, Taku; Suda, Shigeyuki; Higashinaka, Motonori; Ikawa, Takeshi

doi:10.1016/j.tecto.2008.05.009

Cited by 13 publications

(18 citation statements)

References 17 publications

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“…The structural parameters are listed in Table 1. Figure 4 shows the isodepth contours of the upper boundary surface of the descending Philippine Sea plate, which are slightly modified from the CAMP model (Hashimoto et al 2004) by adding a small-scale bump near the tip of the Boso peninsula found by Tsumura et al (2009). The spatial distribution of each slip-vector component f G1(2) (ξ) on the plate interface is represented by the superposition of 129 normalized bi-cubic Bsplines at 8-km intervals.…”

Section: Coseismic Slip Distribution Of the 1703 Genroku Eventmentioning

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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Section: Coseismic Slip Distribution Of the 1703 Genroku Eventmentioning

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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“…their strike and dip, by establishing the cross-dip component. We have applied an azimuthal binning procedure (Tsumura et al, 2009;Kashubin and Juhlin, 2010;Lundberg and Juhlin, in press) and the cross-dip analysis method described by Wu et al (1995) to the data in order to extract the orientation of the assumed fault plane reflections. Where scattering of midpoints is significant, the azimuthal binning procedure did improve the seismic image along the profiles.…”

Section: Cross-dip Analysismentioning

confidence: 99%

Constraints on the geometry of the Suasselkä post-glacial fault, northern Finland, based on reflection seismic imaging

et al. 2015

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“…11) (e.g. Sato et al, 2005;Tsumura et al, 2009). It is believed that, in the case of the 1923 Taisho Earthquake, the tectonic Figure. 2.…”

Section: Figure 2 Coseismic Vertical Crustal Movements During the 17mentioning

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History of the paleo-earthquakes along the Sagami Trough, central Japan: Review of coastal paleoseismological studies in the Kanto region

Shishikura

2014

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North American Plate (Fig. 1). While historical records show that two great earthquakes, the 1703 Genroku Kanto Earthquake (M 8.2) and the 1923 Taisho Kanto Earthquake (M 7.9) (hereafter, the 1703 Genroku Earthquake and the 1923 Taisho Earthquake, respectively), occurred along this trough (Usami et al., 2013), records of earthquakes occurring before the 1703 Genroku Earthquake are ambiguous. However, instead of concentrating on the few remaining historical records of past eras, tectonic geomorphological studies have aimed at recovering information on past earthquakes from marine terraces. Such studies have been conducted since the coseismic uplift associated with the 1923 Taisho Earthquake was discovered along the coasts facing the Sagami Trough (Imamura, 1925; Watanabe, 1929). Although the progress of paleoseismological records of the past 40 years in this area has helped elucidate the history and cycle of interplate earthquakes along the Sagami Trough (e.g. Shishikura, 2003), the observed results do not fully agree with more recently obtained geodetical observation data. The resulting contradictions are very important, not only in terms of scientific understanding, but also because of their relevance when formulating disaster prevention plans for metropolitan areas. In fact, Japanese government offices tasked with disaster prevention measures have recently announced seismic hazard breakdowns for Japan's metropolitan areas (Cabinet Office, 2013; Earthquake Research Committee, 2014), but those efforts did not consider this problem in detail. Therefore, in this paper, I will provide an overview of current research into paleoearthquakes and associated tsunami events in this region, discuss the distribution of the region's seismically active faults, and then examine their possible slip recurrence, terrace uplift magnitudes, and tsunami deposit records. Historical earthquakes and tsunamis along the Sagami Trough 1923 Taisho Kanto Earthquake The 1923 Taisho Kanto Earthquake, which killed more than 105,000 people, was one of the worst natural disasters in recorded Japanese history (Moroi and Takemura, 2004). Significant crustal movements and tsunamis accompanied this earthquake. According to tide gauge data and the re-leveling of benchmarks and triangular points undertaken by the Land Survey Department (1926), the Boso Peninsula, Miura Peninsula, and Oiso coastal area Two subduction zone interplate earthquakes have been recorded along the Sagami Trough, the first in AD 1703 (Genroku Earthquake) and the second in AD 1923 (Taisho Earthquake). While the source areas of these two events overlapped within and around the Sagami Bay, the 1703 Genroku Earthquake had a larger rupture area, which propagated to off the Boso Peninsula. Currently, our understanding of prehistorical earthquakes has been facilitated by Holocene marine terraces and tsunami deposits, through which we have come to the understanding that past Kanto earthquakes can be divided into two types-the Taisho-type and the Genrokutype. Taisho-type earthquakes are ...

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A bump on the upper surface of the Philippine Sea plate beneath the Boso Peninsula, Japan inferred from seismic reflection surveys: A possible asperity of the 1703 Genroku earthquake

Cited by 13 publications

References 17 publications

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

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

Constraints on the geometry of the Suasselkä post-glacial fault, northern Finland, based on reflection seismic imaging

History of the paleo-earthquakes along the Sagami Trough, central Japan: Review of coastal paleoseismological studies in the Kanto region

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