Stress transfer among en echelon and opposing thrusts and tear faults: Triggering caused by the 2003 Mw=6.9 Zemmouri, Algeria, earthquake
Stress transfer among en echelon and opposing thrusts and tear faults: Triggering caused by the 2003 Mw=6.9 Zemmouri, Algeria, earthquake
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DOI：
10.1029/2010jb007654
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发表时间：
2011-03-23
影响因子：
3.9
通讯作者：
Belabbes, Samir
中科院分区：
文献类型：
--
作者：
Lin, Jian;Stein, Ross S.;Belabbes, Samir
首先通过理想化的实例，然后通过对阿尔及利亚逆冲断裂作用的研究，研究了梯形逆冲断层和撕裂断层上地震之间应力相互作用的基本特征。我们计算了2003年M-W=6.9 Zemmori地震引起的同震应力变化，发现绝大多数Zemmori余滑点由于同震应力使更接近库仑破坏的几个杆，而大多数余震节面平均接近2巴。此外，我们计算了相邻的泰尼亚断裂的浅部，它持续了类似于0.25米的滑动，使>；2条更接近于破裂。我们计算出，在邻近的布默德斯逆冲断层的深部，库仑应力增加了1.5bar，该逆冲断层距离阿尔及尔市只有10-20公里；布默德斯断层和特尼亚断层都受到余震的照亮。在接下来的6年里，整个南倾逆冲系统向西南延伸了80公里，经历了地震活动的增加。Zemmori断裂以西的萨赫勒逆冲断层东部的应力也增加了0.4bar。阿尔及尔在公元1365年和1716年遭受了巨大的破坏性地震，现在是300万人的家园。如果这些地震发生在萨赫勒东部断裂上，如果它的构造加载速率类似于2毫米/年，那么已经积累了足够的载荷来产生今天的M-W=6.6-6.9次地震。因此，这些潜在的致命断层需要更好地了解它们的滑动速率和地震历史。
The essential features of stress interaction among earthquakes on en echelon thrusts and tear faults were investigated, first through idealized examples and then by study of thrust faulting in Algeria. We calculated coseismic stress changes caused by the 2003 M-w = 6.9 Zemmouri earthquake, finding that a large majority of the Zemmouri afterslip sites were brought several bars closer to Coulomb failure by the coseismic stresses, while the majority of aftershock nodal planes were brought closer to failure by an average of similar to 2 bars. Further, we calculated that the shallow portions of the adjacent Thenia tear fault, which sustained similar to 0.25 m slip, were brought >2 bars closer to failure. We calculated that the Coulomb stress increased by 1.5 bars on the deeper portions of the adjacent Boumerdes thrust, which lies just 10-20 km from the city of Algiers; both the Boumerdes and Thenia faults were illuminated by aftershocks. Over the next 6 years, the entire south dipping thrust system extending 80 km to the southwest experienced an increased rate of seismicity. The stress also increased by 0.4 bar on the east Sahel thrust fault west of the Zemmouri rupture. Algiers suffered large damaging earthquakes in A. D. 1365 and 1716 and is today home to 3 million people. If these shocks occurred on the east Sahel fault and if it has a similar to 2 mm/yr tectonic loading rate, then enough loading has accumulated to produce a M-w = 6.6-6.9 shock today. Thus, these potentially lethal faults need better understanding of their slip rate and earthquake history.