Analysis of the 9 September 1998 Mw 5.6 Mercure earthquake sequence (Southern Apennines, Italy): A multidisciplinary approach
Analysis of the 9 September 1998 Mw 5.6 Mercure earthquake sequence (Southern Apennines, Italy): A multidisciplinary approach
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DOI：
10.1016/j.tecto.2008.12.007
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发表时间：
2009-10-15
期刊：
影响因子：
2.9
通讯作者：
Cardinali, M.
中科院分区：
文献类型：
--
作者：
Brozzetti, F.;Lavecchia, G.;Cardinali, M.
1998年9月9日Mercure地震（Mw 5.6）及其余震发生在亚平宁南部的一个小型更新世-全新世大陆盆地，该地区仪器地震活动性低，历史地震活动性中等。对地震、光地质和野外调查数据进行分析和整合，以确定可能的发震构造，描绘其三维几何和运动学，并进一步限制研究区域破裂过程的发震潜力。主震发生在地震序列的西北边缘（北纬40.03度和15.95度），深度为10.5 +/- 1.5 Km。余震震量是根据1998年9月10日至10月12日当地地震台网记录的约200次余震（1.1 = MI = 3.9）的重新定位确定的。重新定位过程是基于为所有事件选择P波和S波，并定义适合不同台站的10个9层速度模型。通过计算36个约束良好的震源机制，确定了发震变形的运动学。通过震源机制反演和断层滑动数据反演，确定了地震和地质应力张量，两者均为张拉型，分别为ENE-WSW和NE-SW走向sigma(3)轴。余震序列的分布图和剖面分布表现为平均北西-东向、西倾60度的发震体积。大多数事件（80%）位于Mercure盆地（MBB）边界断层下盘3至8公里的深度，但可能沿着先前未确定的小丑夹延续。全新世正断层走向N120°E，西向西倾，从Castello Seluci延伸至Piana Perretti和Timpa della Manca （CPST断层）。一小部分事件（10%）位于CPST发震断层可能分离的10至12公里深度之间。1998年水星地震的重建破裂区（RA）沿走向长度(L)约为9 km，下倾宽度(W)约为9 km，总面积约为81 km(2)。另一方面，确定了导致地震的整个单个发震构造的L和W维度，例如CPST断层。分别约有19宗和12宗被杀，因此面积约为230平方公里。这可能意味着最大震级（Mw）等于6.3，这导致LIS将Mercure地区与相邻的Pollino-Castrovillari地区进行比较，该地区记录了强烈的古地震事件(C) 2008 Elsevier B.V.。
The Mercure earthquake (Mw 5.6) of September 9, 1998 and the associated aftershocks occurred in a small Pleistocene-Holocene continental basin of the Southern Apennines, in a region of low instrumental and moderate historical seismicity. Seismological, photogeological and field survey data were analyzed and integrated in order to identify the likely seismogenic structure, to depict its 3-D geometry and kinematics and to provide further constraints to the seismogenic potential of the rupture processes in the study area. The mainshock occurred at the NW edge of the seismic sequence (40.03 degrees N and 15.95 degrees) at a depth of 10.5 +/- 1.5 Km. The aftershocks volume was determined from the relocation of about 200 events (1.1 = MI = 3.9) registered by local networks from September 10 to October 12, 1998. The relocation procedure was based on choosing P and S waves for all the events and the definition of ten 9-layers velocity models appropriate for the different stations. The kinematics of the seismogenic deformation was defined through the computation of 36 well-constrained focal mechanisms. The seismological and geological stress tensors were determined through inversion of focal mechanisms and fault slip data Both of them resulted in the tensional type, with ENE-WSW and NE-SW trending sigma(3) axis, respectively. The map and the section distribution of the aftershocks sequence depicts an average NW-SE striking and 60 degrees SW-dipping seismogenic volume. Most of the events (80%) were located at depths between 3 and 8 km in the footwall of the Mercure basin (MBB) boundary fault but along the possible clown-clip continuation of a previously unidentified. N120 degrees E striking and WSW-dipping, Holocene normal fault alignment, which extends from Castello Seluci to Piana Perretti and Timpa della Manca (CPST fault). A small percentage of events (10%) were located at depths between 10 and 12 km where the CPST seismogenic fault may detach.The reconstructed rupture area (RA) of the Mercure 1998 earthquake has an along-strike length (L) of about 9 km and a down-dip width (W) of about 9 km, yielding a total area of approximately 81 km(2) On the other hand, the L and W dimension of the entire individual seismogenic structure identified as responsible for the earthquake, e.g. the CPST fault. are about 19 and 12 kill, respectively, with a consequent RA of about 230 km2. This may imply a maximum magnitude (Mw) equal to 6 3 which lead LIS to compare the Mercure area, in terms of seismogenic hazard, to the adjacent Pollino-Castrovillari area where strong paleoseismological events are documented (C) 2008 Elsevier B.V. All rights reserved.