1994 offshore Sanriku earthquake

Earthquake in Japan 1994 offshore Sanriku earthquake 1994-12-28 12:19:23 usp0006qh3 137333 December 28, 1994 21:19 Japan 7.7 w y7.5 jma y 33 km 40.451 N 143.491 E Japan 55 cm 0.69 g 673.5 Gal 9Significant Earthquake Database https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-data?minIntensity=9&minYear=1900&maxIntensity=12&minDeaths=0&minEqMagnitude=6&minDeathsTotal=0 National Geophysical Data Center / World Data Service (NGDC/WDS) National Geophysical Data Center, NOAA 10.7289/V5TD9V7K 1972 Data Set 6+ 3 killed, 788 injured 250px JMA seismic intensity map 250px Location of the epicenter The 1994 offshore Sanriku earthquake (Japanese: 三陸はるか沖地震 Sanriku Haruka Okijishin) occurred on December 28, 1994, at 12:19 UTC (21:19 JST). This was a magnitude w y 7.7 earthquake with epicenter located in the Pacific Ocean at about 180 km east of Hachinohe, Aomori (haruka-oki means "far offshore").https://earthquake.usgs.gov/earthquakes/eqarchives/significant/sig_1994.php Significant Earthquakes of the World 1994 United States Geological Survey 5 January 2010 13 July 2011 https://web.archive.org/web/20110714105610/http://earthquake.usgs.gov/earthquakes/eqarchives/significant/sig_1994.php 2011-07-14 deadhttp://www.bousai.pref.aomori.jp/jisinsouran/sanriku/1_jisin_target.htm Summary of earthquake Disaster Prevention Aomori Prefecture Japanese 13 July 2011 https://web.archive.org/web/20120131024646/http://www.bousai.pref.aomori.jp/jisinsouran/sanriku/1_jisin_target.htm 2012-01-31 dead The intensity reached shindo 6 in Hachinohe, Aomori, about 187.6 km from epicenter. It could be felt in Tokyo, about 632.9 km from epicenter, with shindo 2.http://www.seisvol.kishou.go.jp/eq/kyoshin/jishin/sanrikuharukaoki/table.htm 強震波形（三陸沖） 2011-08-09 https://web.archive.org/web/20110928024108/http://www.seisvol.kishou.go.jp/eq/kyoshin/jishin/sanrikuharukaoki/table.htm 2011-09-28 dead ja The Japanese Meteorological Agency put the magnitude at jma y 7.5.Sato Y. Ichii K. Miyata M. Morita T. Iai S amp 1997 Strong-motion earthquake records on the 1994 Sanriku-Haruka-Oki earthquake in port areas Technical Note of the Port and Harbour Research Institute, Ministry of Transport, Japan 892 5 http://www.pari.go.jp/search-pdf/no0892.pdf 13 July 2011 26 March 2012 https://web.archive.org/web/20120326184829/http://www.pari.go.jp/search-pdf/no0892.pdf dead Slip associated with this earthquake continued for more than a year and it has been termed an 'ultra-slow earthquake'. Geology The northern part of Honshu and Hokkaido lie above the convergent plate boundary, where the Pacific plate is subducting beneath the Okhotsk microplate. The convergence rate across this boundary lies in the range of 7.9–9.2 cm per year.Nishimura T. Miura S. Tachibana K. Hashimoto K. Sato T. Hori S. Murakami E. Kono T. Nida K. Mishina M. Hirasawa T. Miyazaki S. amp 2000 Distribution of seismic coupling on the subducting plate boundary in northeastern Japan inferred from GPS observations Tectonophysics 323 3–4 217–238 10.1016/S0040-1951(00)00108-6 2000Tectp.323..217N The plate interface in the area of the earthquake epicenter shows an abrupt increase in dip from about 5° to about 15°, 80 km landward of the Japan Trench.Ito A. Fujie G. Tsuru T. Kodaira S. Nakanishi A. Kaneda Y. amp 2004 Fault plane geometry in the source region of the 1994 Sanriku-oki earthquake Earth and Planetary Science Letters 223 1–2 163–175 10.1016/j.epsl.2004.04.007 2004E&PSL.223..163I This part of the plate boundary has been the location of many powerful historical earthquakes, dating back to the 869 Sanriku earthquake and most recently of the devastating 2011 Tōhoku earthquake. Most of these events relate to rupture along the plate interface, but some, such as the 1933 Sanriku earthquake,Kanamori H. Hiroo Kanamori Seismological evidence for a lithospheric normal faulting – the Sanriku earthquake of 1933 Physics of the Earth and Planetary Interiors 4 4 289–300 10.1016/0031-9201(71)90013-6 http://www.gps.caltech.edu/uploads/File/People/kanamori/HKpepi71.pdf 13 July 2011 1971PEPI....4..289K 1971 https://web.archive.org/web/20120319210826/http://www.gps.caltech.edu/uploads/File/People/kanamori/HKpepi71.pdf 2012-03-19 dead involved deformation within the subducting plate. According to the studies of past great earthquakes, a weak seismic coupling is suggested in the offshore Sanriku region.Takahashi N. Kodaira S. Tsuru T. Park J-O. Kaneda Y. Suyehiro K. Kinoshita H. Abe S. Nishino M. Hino R. amp Seismic structure and seismogenesis off Sanriku region, northeastern Japan Geophysical Journal International 159 1 129–145 10.1111/j.1365-246X.2004.02350.x 2004GeoJI.159..129T 2004 free From the distribution of past seismicity, the width of coupling at 40°N was assumed to be about 150 km.Kawasaki I. Asai Y. Tamura Y. amp 2001 Space–time distribution of interplate moment release including slow earthquakes and the seismo-geodetic coupling in the Sanriku-oki region along the Japan trench Tectonophysics 330 3–4 276–283 10.1016/S0040-1951(00)00245-6 http://www.rcep.dpri.kyoto-u.ac.jp/~kawasaki/paper-E01tectono.pdf 13 July 2011 2001Tectp.330..267K In 1999, an investigation was conducted in the source regions of the 1968 offshore Tokachi earthquake and the 1994 offshore Sanriku earthquake. It was found that the structures of crust are heterogeneous in the north and south of 40°10' N. The thickness of the crust is 21 km in the north and 15 km in the south. The P wave velocity in the north is 7% slower than that in the south.Heterogeneous structure across the source regions of the 1968 Tokachi-Oki and the 1994 Sanriku-Haruka-Oki earthquakes at the Japan Trench revealed by an ocean bottom seismic survey Physics of the Earth and Planetary Interiors 132 1–3 89–104 2002 Hayakawa Tadaaki Kasahara Junzo Hino Ryota Sato Toshinori Shinohara Masanao Kamimura Aya Nishino Minoru Sato Takeshi Kanazawa Toshihiko 2002PEPI..132...89H 10.1016/S0031-9201(02)00046-8 Earthquake This was an interplate earthquake,Igarashi T. Matsuzawa T. Hasegawa A. amp 2003 Repeating earthquakes and interplate aseismic slip in the northeastern Japan subduction zone Journal of Geophysical Research 108 B5 2249 10.1029/2002JB001920 ftp://ftp.gps.caltech.edu/pub/avouac/Ge277-2007-fall/Igarashi_JGR2003.pdf 2003JGRB..108.2249I https://web.archive.org/web/20160310140646/ftp://ftp.gps.caltech.edu/pub/avouac/Ge277-2007-fall/Igarashi_JGR2003.pdf 2016-03-10 dead free with a low-angle reverse fault focal mechanism, which ruptured part of the plate interface. The region of the largest slip in this earthquake coincides with the region of low seismic moment release in the 1968 Offshore Tokachi earthquake on May 16, 1968, implying that the 1994 Offshore Sanriku earthquake completed the incompleted fault slip in the source region of the 1968 Offshore Tokachi earthquake.Nishimura T. Nakahara H. Sato H. Ohtake M. amp 1996 Source Process of the 1994 Far East Off Sanriku Earthquake, Japan, as Inferred from a Broad-Band Seismogram Tohoku Geophysical Journal 34 4 121–134 http://ir.library.tohoku.ac.jp/re/bitstream/10097/45347/1/AA0045942696971.pdf 13 July 2011 https://web.archive.org/web/20120602075924/http://ir.library.tohoku.ac.jp/re/bitstream/10097/45347/1/AA0045942696971.pdf 2012-06-02 dead The average slip of the fault was estimated to be 0.4 m and the maximal slip about 1.2 m. The slip caused by this earthquake can be divided into a coseismic slip that occurred immediately before, during and immediately after the event, and a long period of slow post-seismic slip that continued for more than a year after the original event. The slow post-seismic slip following this earthquake had a large seismic moment compared with the coseismic slip associated with the main event. The post-seismic slip occurred in two phases; an initial faster short-term phase that lasted for about ten days, terminating with the largest aftershock, followed by a long-term slower phase. The slip area of the initial phase matches the rupture area for the main event. The second phase migrated significantly further down-dip and to the south, along the plate boundary. The main event released a seismic moment of about 3×1020 Nm, corresponding to magnitude w 7.59. However, the total seismic moment released by the main event and the following slow slip events up to about 1 year thereafter was about 8×1020 Nm, which corresponds to magnitude w 7.84.http://www.rcep.dpri.kyoto-u.ac.jp/~kawasaki/subj1-sse.pdf Silent earthquake – what is the origin of slow earthquakes? Kawasaki I. Japanese 13 July 2011 The seismic moment of the earthquake was put at 4.3×1020 Nm by the USGS. The slow slip in the landward side of the source region was found to be larger than that in the trenchward side of the source region.http://www.aob.gp.tohoku.ac.jp/~uchida/kenkyuu/02arasuka.pdf Spatio-temporal distribution of afterslip of the 1994 Far-off-Sanriku earthquake, Japan, estimated from repeating earthquake analyses Uchida N. Igarashi T. Matsuzawa T. Hasegawa A. amp 2002 13 July 2011September 2018 InternetArchiveBot yes The maximum accelerations recorded in Hachinohe were 602.3 cm/s2 in NS, 488.4 cm/s2 in EW, and 94.1 cm/s2 in UD. Tsunami A local tsunami was triggered by this earthquake. The recorded maximum height of the tsunami was in Miyako, which was about 55 cm.https://www.hp1039.jishin.go.jp/eqchr/4-2-4.htm 平成６年（１９９４年）三陸はるか沖地震（１９９４年１２月２８日、Ｍ７．５） hp1039.jishin.go.jp ja In Ayukawa, Miyagi Prefecture and in Hachinohe, Aomori Prefecture, the tsunami was about 50 cm high.http://www.ngdc.noaa.gov/nndc/struts/results?EQ_0=2235&t=101650&s=9&d=92,183&nd=display https://web.archive.org/web/20200831225908/https://www.ngdc.noaa.gov/nndc/struts/results?EQ_0=2235&t=101650&s=9&d=92,183&nd=display dead August 31, 2020 Tsunami Event NGDC 13 July 2011 There was no report of damage caused by the tsunami. Aftershocks The locations of the most part of the aftershocks were within a 170 km × 84 km region west of the initial break of the main shock. Most of the aftershocks occurred in the region of small slip in the main rupture. The strongest aftershock occurred on January 6, 1995, at 22:37 UTC (January 7, 1995, at 07:37 local time) with magnitude w 6.9, leaving 29 people injured. It was located at 40.246 N, 142.175 E with a depth of 27 km. The intensity reached shindo 5 in Hachinohe, Aomori.https://earthquake.usgs.gov/earthquakes/eqarchives/significant/sig_1995.php Significant Earthquakes of the World 1995 United States Geological Survey 5 January 2010 13 July 2011 https://web.archive.org/web/20110608020600/http://earthquake.usgs.gov/earthquakes/eqarchives/significant/sig_1995.php 8 June 2011 dead This aftershock could be felt in Tokyo with shindo 2.April 2026 Damage The felt intensity of the earthquake reached Shindo 6 in Hachinohe and Misawa, Shindo 5 at Aomori, Morioka and Mutsu and Shindo 4 at Miyako, Ofunato, Hakodate, Obihiro, Tomakomai and Urakawa. In the prefectures of Aomori and Iwate, about 69,000 households had no electricity.http://www.nishinippon.co.jp/saigai/html/1994/s199412.html 今月の災害・事故 --（平成６年）1994年12月 2012-03-31 https://web.archive.org/web/20110919032318/http://www.nishinippon.co.jp/saigai/html/1994/s199412.html 2011-09-19 dead ja A total of 6,229 buildings were affected, with 48 completely destroyed, 378 partially destroyed and another 5,803 suffering some damage. The total damage was estimated at 170.4 million US dollars. Three people were reported dead and more than 200 injured;http://www.ngdc.noaa.gov/nndc/struts/results?eq_0=5397&t=101650&s=13&d=22,26,13,12&nd=display https://web.archive.org/web/20160126180342/http://www.ngdc.noaa.gov/nndc/struts/results?eq_0=5397&t=101650&s=13&d=22,26,13,12&nd=display dead January 26, 2016 Comments for the Significant Earthquake NGDC 13 July 2011 48 houses were completely destroyed. Road damage and power outages were reported. Liquefaction occurred in the Hachinohe Port area.http://www.bousai.pref.aomori.jp/jisinsouran/sanriku/2_higai_target.htm Summary of damage Disaster Prevention Aomori Prefecture Japanese 13 July 2011 https://web.archive.org/web/20110324192420/http://www.bousai.pref.aomori.jp/jisinsouran/sanriku/2_higai_target.htm 2011-03-24 dead See also List of earthquakes in 1994 List of earthquakes in Japan References External links 137333 Offshore Sanriku earthquake Offshore Sanriku Offshore Sanriku earthquake Offshore Sanriku earthquake Category:Earthquakes of the Heisei era Category:Tsunamis in Japan Offshore Sanriku earthquake