【摘要】 概述了2001年11月14日发生在新疆、青海交界的昆仑山口西地震震级的测定过程,分析比较了我国国家数字地震台网和美国地质调查局(USGS)国家地震信息中心(NEIC)测定的面波震级MS,以及国内外不同机构测定的该地震的矩震级MW.结果表明,不同的机构在测定面波震级时,由于所使用的资料不尽相同,所使用的计算震级的公式也有所不同,导致测定结果有一定的差别.我国对该地震的速报结果是MS=8.1,在正式编辑出版的《中国数字地震台网观测报告》中给出的测定结果是MS=8.2;美国地质调查局(USGS)国家地震信息中心(NEIC)测定的结果是MS=8.0.地震发生后不久,哈佛大学(Harvard)、NEIC、东京大学地震研究所(ERI)、中国地震局分析预报中心(APCEA)、中国地震局地球物理研究所(IG-CEA)利用全球地震台网、中国国家数字地震台网或中国数字地震台网(CDSN)的资料得出的矩震级MW分别是7.8(Harvard),7.7(NEIC),7.7(ERI),7.6(APCEA),7.5(IGCEA),测定的结果基本一致,平均为MW=7.7.鉴于矩震级是一个描述地震绝对大小的力学量,与传统的震级标度相比具有明显的优点,国际地震学界推荐矩震级作为优先使用的震级.本文分析表明,昆仑山口西地震的震级(矩震级)为MW=7.7,其面波震级MS=8.0,是一次面波震级未饱和的地震.更多还原

【Abstract】 This paper presents an overview of the magnitude determination of the November 14, 2001 earthquake west of Kunlun Mountain Pass (KMP) at the juncture of Xinjiang and Qinghai, northwestern China. Comparisons are made among surface wave magnitudes determined by China National Digital Seismograph Network (CNDSN), National Earthquake Information Center (NEIC) of US Geological Survey (USGS) and moment magnitudes determined by different institutions in China and abroad. The results show that different institutions yield different surface wave magnitudes, as different data and calculation formulae are used in magnitude determination. The magnitude of the earthquake in “China′s Rapid Earthquake Information Release” was given as M_S=8.1; Measurement given in the formally edited and published “Observation Report of China Digital Seismograph Network” is M_S=8.2; And magnitude determined by NEIC is M_S=8.0. Soon after the occurrence of the KMP earthquake, Harvard University (Harvard), NEIC, Earthquake Research Institute of University of Tokyo (ERI), Center for Analysis and Prediction, China Earthquake Administration (APCEA) and Institute of Geophysics, China Earthquake Administration (IGCEA) gave the moment magnitude M_W as 7.8(Harvard), 7.7(NEIC), 7.7(ERI), 7.6(APCEA) and 7.5(IGCEA), respectively, based on data from Global Seismograph Network (GSN), CNDSN and China Digital Seismograph Network (CDSN). These measurements, with an average value of M_W=7.7, are close to each other. As moment magnitude is a physical quantity measuring the absolute size of an earthquake and has obvious advantages over conventional magnitude scales, it is the preferred magnitude of the international seismological community. It is concluded that the KMP earthquake is an earthquake with unsaturated surface wave magnitude with moment magnitude M_W=7.7 and surface wave magnitude M_S=8.0.更多还原