2012年加拿大西海岸M_W7.7地震构造背景与区域地震活动
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摘要
2012年10月28日加拿大西海岸发生了MW7.7地震,震中位于板块边界的夏洛特皇后断裂南段,处于环太平洋地震带上,是太平洋板块相对北美板块以约6cm/a的速率,使得断层面应变积累到一定程度引发破裂的结果。历史地震分析表明,该地震正好填充了南段一个多世纪以来存在的空区。该地震的发生可能表明一个新的地震周期的开始,未来几十年内该断裂带上可能以中强地震活动为主,发生8级左右地震的可能性不大。
The 2012Canada earthquake(MW7.7)occurred on the southern segment of the Queen Charlotte fault,which lies on the Circum-Pacific seismic belt and separates the Pacific plate from the Northern American plate.The motion of the Pacific plate with a rate of ～6cm/a along the Queen Charlotte fault with respect to the Northern American plate generated the accumulation and release of strain on the fault plane to a critical level and finally ruptured during the 2012 MW7.7earthquake.The occurrence of the 2012earthquake filled the seismic gap found in previous studies on the rupture of historical earthquakes.This earthquake may indicate the starting of a new seismic cycle.In the coming decades,intermediate-strong earthquakes may dominate and there is a low level of possibility for an earthquake with magnitude～8.
The 2012Canada earthquake(MW7.7)occurred on the southern segment of the Queen Charlotte fault,which lies on the Circum-Pacific seismic belt and separates the Pacific plate from the Northern American plate.The motion of the Pacific plate with a rate of ～6cm/a along the Queen Charlotte fault with respect to the Northern American plate generated the accumulation and release of strain on the fault plane to a critical level and finally ruptured during the 2012 MW7.7earthquake.The occurrence of the 2012earthquake filled the seismic gap found in previous studies on the rupture of historical earthquakes.This earthquake may indicate the starting of a new seismic cycle.In the coming decades,intermediate-strong earthquakes may dominate and there is a low level of possibility for an earthquake with magnitude～8.
引文
[1]http:∥earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usb000df7n.php
[2]Poster of the Haida Gwaii Region,Canada Earthquake of 28October 2012-Magnitude 7.7.http:∥earth-quake.usgs.gov/earthquakes/eqarchives/poster/2012/20121028.php
[3]Nobuo H.Aftershock distribution and the mainshock’s fault plane by the MJHD method:App-lication to the Myanmar Earthquake on November 11,2012.http:∥iisee.kenken.go.jp/special2/20121111myanmar/201211Myanmar-MJHD.pdf.2012
[4]http:∥earthquake.usgs.gov/earthquakes/world/index.php?region=Canada
[5]Haggart J W,Matsukawa M,Ito M.Paleogeographic and paleoclimatic setting of Lower Cretaceous ba-sins of East Asia and western North America,with reference to the nonmarine strata.Cretaceous Re-search,2006,27(2):149-167
[6]Yeats R.Active Faults of the World.Cambridge University Press,2012
[7]http:∥www.globalcmt.org/CMTsearch.html
[8]http:∥www.ceme.gsras.ru/cgi-bin/info_quakee.pl?mode=1&id=194
[9]任俊杰,周娜.2010年智利大地震及历史地震活动与地质构造背景.国际地震动态,2010(3):1-7
[10]Goldfinger C,Morey A E,Nelson C H,et al.Rupture lengths and temporal history of significant earth-quakes on the offshore and north coast segments of the Northern San Andreas Fault based on turbiditestratigraphy.Earth and Planetary Science Letters,2007,254(1):9-27
[11]Goldfinger C,Nelson C H,Johnson J E.Holocene earthquake records from the Cascadia subduction zoneand northern San Andreas Fault based on precise dating of offshore turbidites.Annual Review of Earthand Planetary Sciences,2003,31(1):555-577
[12]Mazzotti S,Hyndman R D,Flück P,et al.Distribution of the Pacific/North America motion in theQueen Charlotte Islands-S.Alaska plate boundary zone.Geophys.Res.Lett.,2003,30(14):1762-1768
[13]Brown E H,Housen B A,Schermer E R.Tectonic evolution of the San Juan Islands thrust system,infloods,faults,and fire:Geological field trips in Washington State and Southwest British Columbia.Stelling P,Tucker D S,Eds.Geological Society of America Field Guide 9,2007
[14]Bufe C G.Stress distribution along the Fairwether-Queen Charlotte transform fault system.Bull.Seis.Soc.Amer.,2005,95(5):2001-2008
[15]http:∥www.teacherfurse.com/PhysicsPage/Classes/Science10/EarthScience/EarthQuakes/volcano_earthquake.htm
[16]Rogers G C.Seismic gaps along the Queen Charlotte fault.Earthquake Prediction Research,1986,4(1-2):1-11
[2]Poster of the Haida Gwaii Region,Canada Earthquake of 28October 2012-Magnitude 7.7.http:∥earth-quake.usgs.gov/earthquakes/eqarchives/poster/2012/20121028.php
[3]Nobuo H.Aftershock distribution and the mainshock’s fault plane by the MJHD method:App-lication to the Myanmar Earthquake on November 11,2012.http:∥iisee.kenken.go.jp/special2/20121111myanmar/201211Myanmar-MJHD.pdf.2012
[4]http:∥earthquake.usgs.gov/earthquakes/world/index.php?region=Canada
[5]Haggart J W,Matsukawa M,Ito M.Paleogeographic and paleoclimatic setting of Lower Cretaceous ba-sins of East Asia and western North America,with reference to the nonmarine strata.Cretaceous Re-search,2006,27(2):149-167
[6]Yeats R.Active Faults of the World.Cambridge University Press,2012
[7]http:∥www.globalcmt.org/CMTsearch.html
[8]http:∥www.ceme.gsras.ru/cgi-bin/info_quakee.pl?mode=1&id=194
[9]任俊杰,周娜.2010年智利大地震及历史地震活动与地质构造背景.国际地震动态,2010(3):1-7
[10]Goldfinger C,Morey A E,Nelson C H,et al.Rupture lengths and temporal history of significant earth-quakes on the offshore and north coast segments of the Northern San Andreas Fault based on turbiditestratigraphy.Earth and Planetary Science Letters,2007,254(1):9-27
[11]Goldfinger C,Nelson C H,Johnson J E.Holocene earthquake records from the Cascadia subduction zoneand northern San Andreas Fault based on precise dating of offshore turbidites.Annual Review of Earthand Planetary Sciences,2003,31(1):555-577
[12]Mazzotti S,Hyndman R D,Flück P,et al.Distribution of the Pacific/North America motion in theQueen Charlotte Islands-S.Alaska plate boundary zone.Geophys.Res.Lett.,2003,30(14):1762-1768
[13]Brown E H,Housen B A,Schermer E R.Tectonic evolution of the San Juan Islands thrust system,infloods,faults,and fire:Geological field trips in Washington State and Southwest British Columbia.Stelling P,Tucker D S,Eds.Geological Society of America Field Guide 9,2007
[14]Bufe C G.Stress distribution along the Fairwether-Queen Charlotte transform fault system.Bull.Seis.Soc.Amer.,2005,95(5):2001-2008
[15]http:∥www.teacherfurse.com/PhysicsPage/Classes/Science10/EarthScience/EarthQuakes/volcano_earthquake.htm
[16]Rogers G C.Seismic gaps along the Queen Charlotte fault.Earthquake Prediction Research,1986,4(1-2):1-11
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