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2011年4月11日日本东北福岛县浜通地震于2011年3月11日东北地方太平洋海岸近海地震之后1个月发生在一地震活动区。这次浜通地震在北北西—南南东走向的系沢断层上造成14km长向西的正滑破裂,同时在西北西—东南东走向的汤野岳断层造成16km长向南的正滑破裂。沿系沢断层的滑动从南端到中部突然增加,其中测量的最大位移近2m;该断层的中段到北西端的滑动逐渐降低。汤野岳断层也有不对称的滑动分布,在其北西段附近峰值约为0.9m。从破裂沿这两条断层扩展的方向来考虑,显然测量到的地表断错在走向上不对称,在更靠近破裂起始的断层末端观测到最大断错,而在破裂终止的方向显现出逐渐减小。滑动分布和震中位置的地表观测结果与滑动反演模型得出的地震破裂的总体特征一致。浜通地震断层超过60%的破裂长度以及其他历史正断层地震,滑动位移量小于或等于最大滑动的30%。根据破裂长度、最大和平均位移估计的该地震的矩震级(MW)在6.5~6.8之间,与地震学确定值6.6相一致。
April 11, 2011 The Hamamatsu earthquake in Fukushima, northeastern Japan, occurred in a seismic activity area one month after the offshore earthquake off the northeast Pacific coast of Japan on March 11, The Hamamatsu earthquake caused a 14-km-long west-easterly slippery rupture on the north-northwest-south-south eastward fault line and a 16-km-long south-easterly slip in the west-southeast-east Tomoyama fault. The slip along the fault line suddenly increased from the southern tip to the middle part, and the maximum displacement was about 2m. The slip between the middle part and the northwest tip of the fault decreased gradually. The Tomoyama fault also has an asymmetrical slip distribution with a peak of about 0.9 m near its northern western segment. Considering from the direction of rupture along these two fault extensions, it is clear that the measured surface rupture is asymmetric in strike direction, the largest fault is observed at the end of the fault nearer to the rupture initiation, and gradually fades to the point where rupture ends Decrease The surface observations of the slip distribution and epicentral location are consistent with the general characteristics of the earthquake rupture resulting from the sliding inversion model. Haotong earthquake fault rupture length of more than 60% and other historical normal fault earthquakes, sliding displacement less than or equal to 30% of the maximum slip. According to the rupture length, the maximum and average displacement estimates of the earthquake moment magnitude (MW) of 6.5 to 6.8, consistent with the seismological determined value of 6.6.