The horizontally lying slab

Kyoko Okino, Masataka Ando, Satoshi Kaneshima, Kazuro Hirahara

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

An unusual earthquake (mb=6.2) occurred in the Izu‐Bonin Island region in July 1982. The event, occurring at a depth of 545 km, was clearly separated from the main inclined seismic zone by a distance of about 200 km. To diagnose the situation, we have considered two possibilities: 1) the event might be an unusual event in the sense that its location is unrelated to the position of the subducted slab and that there is probably no slab around it, or 2) the slab, at this depth, might be lying horizontally on top of the 650 km discontinuity, and the unusual event occurred in this horizontal part. Both possibilities have been modeled structurally. We have computed the P‐wave travel times for the present event, as well as for two other events located unambiguously in the inclined part of the seismic zone by employing a 3‐D ray tracing program. The computed travel time residuals have been compared with the observations at stations in western Japan. The observations are found to be consistent with the model of the horizontally lying slab. Our result, thus, suggests that the slab might be horizontal at this depth in this part of the Izu‐Bonin Islands.

Original languageEnglish
Pages (from-to)1059-1062
Number of pages4
JournalGeophysical Research Letters
Volume16
Issue number9
DOIs
Publication statusPublished - Sep 1989
Externally publishedYes

Fingerprint

slab
slabs
seismic zone
travel time
travel
ray tracing
discontinuity
Japan
earthquakes
stations
earthquake

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

Cite this

The horizontally lying slab. / Okino, Kyoko; Ando, Masataka; Kaneshima, Satoshi; Hirahara, Kazuro.

In: Geophysical Research Letters, Vol. 16, No. 9, 09.1989, p. 1059-1062.

Research output: Contribution to journalArticle

Okino, K, Ando, M, Kaneshima, S & Hirahara, K 1989, 'The horizontally lying slab', Geophysical Research Letters, vol. 16, no. 9, pp. 1059-1062. https://doi.org/10.1029/GL016i009p01059
Okino, Kyoko ; Ando, Masataka ; Kaneshima, Satoshi ; Hirahara, Kazuro. / The horizontally lying slab. In: Geophysical Research Letters. 1989 ; Vol. 16, No. 9. pp. 1059-1062.
@article{2f150e551ea84445b00cee7897190a42,
title = "The horizontally lying slab",
abstract = "An unusual earthquake (mb=6.2) occurred in the Izu‐Bonin Island region in July 1982. The event, occurring at a depth of 545 km, was clearly separated from the main inclined seismic zone by a distance of about 200 km. To diagnose the situation, we have considered two possibilities: 1) the event might be an unusual event in the sense that its location is unrelated to the position of the subducted slab and that there is probably no slab around it, or 2) the slab, at this depth, might be lying horizontally on top of the 650 km discontinuity, and the unusual event occurred in this horizontal part. Both possibilities have been modeled structurally. We have computed the P‐wave travel times for the present event, as well as for two other events located unambiguously in the inclined part of the seismic zone by employing a 3‐D ray tracing program. The computed travel time residuals have been compared with the observations at stations in western Japan. The observations are found to be consistent with the model of the horizontally lying slab. Our result, thus, suggests that the slab might be horizontal at this depth in this part of the Izu‐Bonin Islands.",
author = "Kyoko Okino and Masataka Ando and Satoshi Kaneshima and Kazuro Hirahara",
year = "1989",
month = "9",
doi = "10.1029/GL016i009p01059",
language = "English",
volume = "16",
pages = "1059--1062",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "9",

}

TY - JOUR

T1 - The horizontally lying slab

AU - Okino, Kyoko

AU - Ando, Masataka

AU - Kaneshima, Satoshi

AU - Hirahara, Kazuro

PY - 1989/9

Y1 - 1989/9

N2 - An unusual earthquake (mb=6.2) occurred in the Izu‐Bonin Island region in July 1982. The event, occurring at a depth of 545 km, was clearly separated from the main inclined seismic zone by a distance of about 200 km. To diagnose the situation, we have considered two possibilities: 1) the event might be an unusual event in the sense that its location is unrelated to the position of the subducted slab and that there is probably no slab around it, or 2) the slab, at this depth, might be lying horizontally on top of the 650 km discontinuity, and the unusual event occurred in this horizontal part. Both possibilities have been modeled structurally. We have computed the P‐wave travel times for the present event, as well as for two other events located unambiguously in the inclined part of the seismic zone by employing a 3‐D ray tracing program. The computed travel time residuals have been compared with the observations at stations in western Japan. The observations are found to be consistent with the model of the horizontally lying slab. Our result, thus, suggests that the slab might be horizontal at this depth in this part of the Izu‐Bonin Islands.

AB - An unusual earthquake (mb=6.2) occurred in the Izu‐Bonin Island region in July 1982. The event, occurring at a depth of 545 km, was clearly separated from the main inclined seismic zone by a distance of about 200 km. To diagnose the situation, we have considered two possibilities: 1) the event might be an unusual event in the sense that its location is unrelated to the position of the subducted slab and that there is probably no slab around it, or 2) the slab, at this depth, might be lying horizontally on top of the 650 km discontinuity, and the unusual event occurred in this horizontal part. Both possibilities have been modeled structurally. We have computed the P‐wave travel times for the present event, as well as for two other events located unambiguously in the inclined part of the seismic zone by employing a 3‐D ray tracing program. The computed travel time residuals have been compared with the observations at stations in western Japan. The observations are found to be consistent with the model of the horizontally lying slab. Our result, thus, suggests that the slab might be horizontal at this depth in this part of the Izu‐Bonin Islands.

UR - http://www.scopus.com/inward/record.url?scp=0024928371&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0024928371&partnerID=8YFLogxK

U2 - 10.1029/GL016i009p01059

DO - 10.1029/GL016i009p01059

M3 - Article

AN - SCOPUS:0024928371

VL - 16

SP - 1059

EP - 1062

JO - Geophysical Research Letters

JF - Geophysical Research Letters

SN - 0094-8276

IS - 9

ER -