“1983 Sea of Japan earthquake”的意思、由来-开放百科全书

The 1983 Sea of Japan earthquake or 1983 Nihonkai-Chubu earthquake occurred on May 26, 1983 at 11:59:57 local time (02:59:57 UTC). It had a magnitude of 7.8 on the moment magnitude scale. It occurred in the Sea of Japan, about 100 km west of the coast of Noshiro in Akita Prefecture, Japan. Out of the 104 fatalities, all but four were killed by the resulting tsunami, which struck communities along the coast, especially Aomori and Akita Prefectures and the east coast of Noto Peninsula. Images of the tsunami hitting the fishing harbor of Wajima on Noto Peninsula was broadcast on TV. The waves exceeded {{convert|10|m|sp=us}} in some areas. Three of the fatalities were along the east coast of South Korea (whether North Korea was affected is not known). The tsunami also hit Okushiri Island, the site of a more deadly tsunami 10 years later.

Tectonic setting

The northwestern side of Honshu lies on the southeastern margin of the Sea of Japan, an area of oceanic crust created by back-arc spreading from the late Oligocene to middle Miocene. The extensional tectonics associated with the spreading formed a series of N-S trending extensional faults and associated basins. Currently the area is being deformed by contractional tectonics, causing inversion of these earlier basins, forming anticlinal structures.^[3] It has been suggested that the northwestern coast of Honshu represents an incipient subduction zone,^[1] but there remain significant uncertainties about the existence of the Okhotsk Plate and the nature and precise location of its boundary in the Sea of Japan, if it does exist.^[4]^[5]

Earthquake

The earthquake lasted for about 60 seconds. The focal mechanism indicates reverse faulting and the distribution of aftershocks is consistent with movement on a thrust plane dipping at 30° to the east. The rupture involved two separate faults, the more northerly of which trends NNW-SSE and the more southerly SSW-NNE. The rupture began on the southern fault before continuing on the northern fault after a delay of ten seconds.^[6] The maximum perceived intensity was V on the JMA scale (VIII on the Mercalli intensity scale).^[2]

Tsunami

The first wave of the tsunami struck the coast about 12 minutes after the earthquake, with a maximum run-up height of {{convert|14.9|m|abbr=on}} recorded on the Oga Peninsula.^[7] The initial models of the earthquake were unable to reproduce the short time interval between the shock and the first wave arrival at the coast. The possibility that the faults dipped to the west, which would have brought the tsunami source closer to the coast, was inconsistent with seismic data and slow aseismic slip on the southern fault immediately before the mainshock has been proposed as an explanation.^[6]

Damage

Much of the earthquake damage was due to soil liquefaction, causing the collapse of houses and a number of road and rail accidents. The degree of liquefaction was the worst seen in Japan since the 1964 Niigata earthquake. The greatest effects were observed in areas underlain by loose Holocene aeolian and fluvial sands.^[10] Four people were killed by the effects of the earthquake shaking.^[2]

Tsunami warnings were issued 14 minutes after the earthquake, but many parts of the nearby coast were struck before any action could be taken.^[7] Many people were struck by the first wave either on the shoreline or on offshore building sites and there were a hundred deaths. The tsunami caused widespread damage to coastal defences, which had been designed for storms rather than tsunamis. The tsunami reached the coast of South Korea about 1–1½ hours after the earthquake, causing the death of three people.^[7]

References

1. ^¹{{cite journal|last=Kanamori |first=H. |author2=Astiz L. |year=1985 |title=The 1983 Akita-Oki Earthquake (Mw=7.8) and its Implications for Systematics of Subduction Earthquakes |journal=Earthquake Prediction Research |volume=3 |pages=305–317 |url=http://www.gps.caltech.edu/uploads/File/People/kanamori/HKepr85.pdf |accessdate=21 June 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20131211212533/http://www.gps.caltech.edu/uploads/File/People/kanamori/HKepr85.pdf |archivedate=11 December 2013 |df= }}
2. ^¹²{{cite web|url=http://www.ngdc.noaa.gov/nndc/struts/results?eq_0=4978&t=101650&s=13&d=22,26,13,12&nd=display|title=Comments for the Significant Earthquake|last=National Geophysical Data Center|author-link=National Geophysical Data Center|accessdate=21 June 2012}}
3. ^{{cite journal|last=Sato |first=H. |author2=Yoshida T. |author3=Takaya I. |author4=Sato T. |author5=Ikeda Y. |author6=Umino N. |last-author-amp=yes |year=2004 |title=Late Cenozoic tectonic development of the back arc region of central northern Honshu, Japan, revealed by recent deep seismic profiling |journal=Journal of the Japanese Association for Petroleum Technology |volume=69 |issue=2 |pages=145–154 |issn=0370-9868 |url=http://sciencelinks.jp/j-east/article/200410/000020041004A0325576.php |accessdate=10 June 2010 |doi=10.3720/japt.69.145 |deadurl=yes |archiveurl=https://web.archive.org/web/20120302222953/http://sciencelinks.jp/j-east/article/200410/000020041004A0325576.php |archivedate=2 March 2012 |df= }}
4. ^{{cite journal |first=Tetsuzo |last=Seno |first2=Taro |last2=Sakurai |first3=Seth |last3=Stein |year=1996 |title=Can the Okhotsk plate be discriminated from the North American plate? |journal=Journal of Geophysical Research |volume=101 |issue=B5 |pages=11305–11315 |doi=10.1029/96JB00532 |bibcode = 1996JGR...10111305S }}
5. ^{{citation|url=http://seismo.berkeley.edu/~apel/research/papers/2006GL026077.pdf|last=Apel|first=E. V.|last2=Bürgmann|first2=R.|last3=Steblov|first3=G.|last4=Vasilenko|first4=N.|last5=King|first5=R.|last6=Prytkov|first6=A|year=2006|title=Independent active microplate tectonics of northeast Asia from GPS velocities and block modeling|journal=Geophysical Research Letters|volume=33|pages=L11303|number=L11303|doi=10.1029/2006GL026077|bibcode=2006GeoRL..3311303A|access-date=2012-06-26|archive-url=https://web.archive.org/web/20131213165831/http://seismo.berkeley.edu/~apel/research/papers/2006GL026077.pdf|archive-date=2013-12-13|dead-url=yes|df=}}
6. ^¹{{cite book|last=Shuto|first=N.|author2=Chida K.|author3=Imamura F.|last-author-amp=yes|title=Tsunami: Progress in Prediction, Disaster Prevention, and Warning|editor=Tsuchiya Y.|editor2=Shuto N.|publisher=Springer|year=1995|series=Advances in Natural and Technological Hazards Research|volume=4|pages=37–53|chapter=Generation mechanism of the first wave of the Nihonkai-Chubu earthquake tsunami|isbn=978-0-7923-3483-5|chapter-url=https://books.google.com/books?id=P-2kurlGja8C&pg=PA37|accessdate=21 June 2012}}
7. ^¹²{{cite web|url=http://www.ngdc.noaa.gov/nndc/struts/results?eq_0=4978&t=101650&s=18&d=99,91,95,93&nd=display|title=Comments for the Tsunami Event|author=National Geophysical Data Center|author-link=National Geophysical Data Center|accessdate=21 June 2012}}
8. ^{{cite web|url=http://www.ngdc.noaa.gov/nndc/struts/results?EQ_0=2142&t=102978&s=31&d=34,32|title=Tsunami Event associated with Tsunami Deposits|author=National Geophysical Data Center|author-link=National Geophysical Data Center|accessdate=21 June 2012}}
9. ^{{cite journal|last=Nakajima|first=T.|author2=Kanai Y.|year=2000|title=Sedimentary features of seismoturbidites triggered by the 1983 and older historical earthquakes in the eastern margin of the Japan Sea|journal=Sedimentary Geology|volume=135|issue=1–4|pages=1–19|bibcode = 2000SedG..135....1N |doi = 10.1016/S0037-0738(00)00059-2 }}
10. ^{{cite journal|last=Tohno|first=I.|author2=Shamoto Y.|year=1986|title=Liquefaction damage to the ground during the Nihonkai-Chubu (Japan Sea) earthquake in Aomori Prefecture, Tohoku, Japan|journal=Natural Disaster Science|volume=8|issue=1|pages=85–116|url=http://dl.ndl.go.jp/view/download/digidepo_10752650_po_ART0002966897.pdf?contentNo=1&alternativeNo=|accessdate=21 June 2012}}

Tectonic setting

Earthquake

Tsunami

Damage

References

External links