The Neo-Tec tonic Struc ture of the South west ern Tip of the Oki nawa Trough

Content Provider	Semantic Scholar
Author	Ku, Chia-Yen Hsu, Shu-Kun Sibuet, Jean-Claude Tsai, Ching-Hui
Copyright Year	2009
Abstract	The Ilan Plain is lo cated at the south west ern tip of the Oki nawa Trough backarc ba sin, which prop a gates west ward into the Tai wan orogen. From three mod er ate earth quakes which oc curred near the coast line of the Ilan Plain, one of mag ni tude 6.2 on 15 May 2002 and the other two of mag ni tudes 5.51 and 5.49 on 5 March 2005, we at tempted to un der stand the re la tion ship be tween the earth quake mech a nisms and the geo log i cal con text. Seven seis mic re flec tion pro files col lected roughly par al lel to the coast line of the Ilan Plain were used in this work. A struc tural fault, with a sig nif i cant nor mal fault ing com po nent trending ap prox i mately ENE-WSW, is iden ti fied to the east of the dou blet earth quakes of 5 March 2005. Be cause this fault fol lows the ENE-WSW trend of the after shock seis mic ity, we named it the Ilan Shelf Fault, which might ex tend to the east be yond the Ilan con ti nen tal shelf spur. How ever, the cen troid seis mic mo ment ten sor so lu tions for the dou blet earth quakes of 5 March 2005 are of a left-lat eral strike-slip fault ing type which are con sis tent with onland GPS ob ser va tions. Hence, the Ilan Shelf Fault may have a left-lat eral strike-slip com po nent. Based on GPS data, we sug gest that the north ern Cen tral Range block, bounded in the west by the Lishan Fault and in the north by the Ilan Shelf Fault, ro tates clock wise. This ro ta tion is as cribed to the northwestward col li sion of the Luzon Arc against Tai wan. Thus, there is a left-lat eral strike-slip and an extensional mo tion along the Ilan Shelf Fault. The north ern Cen tral Range block is tilt ing north ward which may also in duce the nor mal fault ing com po nent of the Ilan Shelf Fault. In short, the Ilan Shelf Fault could be a major tectonic and structural feature bounding the southern end of the Okinawa Trough backarc basin.
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Alternate Webpage(s)	http://tao.cgu.org.tw/index.php/articles/archive/oceanic-science/item/download/873_5a139b22600fc9ea6d009921eed011f8
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article