Depth Extent and Kinematics of Faulting in the Southern Tanganyika Rift, Africa
Depth Extent and Kinematics of Faulting in the Southern Tanganyika Rift, Africa
复制标题
非洲坦噶尼喀裂谷南部断层的深度和运动学
DOI：
10.1029/2018tc005379
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发表时间：
2019
期刊：
影响因子：
4.2
通讯作者：
D. Keir
中科院分区：
文献类型：
--
作者：
A. Lavayssière;C. Drooff;C. Ebinger;R. Gallacher;F. Illsley‐Kemp;S. Oliva;D. Keir
在东非裂谷系统中，不寻常的深地震发生在有或没有岩浆活动表面表现的裂谷段之下。坦噶尼喀裂谷是西部裂谷的一部分，没有岩浆活动的表面证据。TANG14台阵部署在坦噶尼喀裂谷南部，那里曾发生过7.4级地震，以探测地壳和上地幔结构并评估断层运动学。2014年6月至2015年9月期间检测到的474次地震使用新的区域速度模型进行定位。利用局部地震和近震的精确位置、震级和震源机制，确定孕震层厚度，圈定活动断层，评价区域伸展方向，评价边界断层的运动学。活动断层跨度超过350公里，深正断层横切厚Bangweulu克拉通，表明一个广泛的板块边界带。孕震层厚度为42公里，横跨裂谷盆地及其隆起侧翼之下的整个地壳。上地幔的地震也被探测到。具有陡峭节面的深源地震沿着坦噶尼喀和鲁夸河边界断层的地下投影发生，表明大偏移（≥5 km）断层穿透到地壳底部，并且是当前的应变轨迹。震源机制、连续深度分布以及与映射构造的相关性表明，在至少1200万年的盆地演化过程中，陡峭的深边界断层保持着半地堑形态。基于我们的研究结果的断层标度表明，M > 7地震沿沿着坦噶尼喀边界断层是可能的。
Unusually deep earthquakes occur beneath rift segments with and without surface expressions of magmatism in the East African Rift system. The Tanganyika rift is part of the Western rift and has no surface evidence of magmatism. The TANG14 array was deployed in the southern Tanganyika rift, where earthquakes of magnitude up to 7.4 have occurred, to probe crust and upper mantle structure and evaluate fault kinematics. Four hundred seventy‐four earthquakes detected between June 2014 and September 2015 are located using a new regional velocity model. The precise locations, magnitudes, and source mechanisms of local and teleseismic earthquakes are used to determine seismogenic layer thickness, delineate active faults, evaluate regional extension direction, and evaluate kinematics of border faults. The active faults span more than 350 km with deep normal faults transecting the thick Bangweulu craton, indicating a wide plate boundary zone. The seismogenic layer thickness is 42 km, spanning the entire crust beneath the rift basins and their uplifted flanks. Earthquakes in the upper mantle are also detected. Deep earthquakes with steep nodal planes occur along subsurface projections of Tanganyika and Rukwa border faults, indicating that large offset (≥5 km) faults penetrate to the base of the crust, and are the current locus of strain. The focal mechanisms, continuous depth distribution, and correlation with mapped structures indicate that steep, deep border faults maintain a half‐graben morphology over at least 12 Myr of basin evolution. Fault scaling based on our results suggests that M > 7 earthquakes along Tanganyika border faults are possible.
U-Pb碎屑锆石地质年代学在油气勘探井钻屑年龄控制中的应用：以坦桑尼亚鲁夸裂谷盆地为例
影响因子：
3.5
作者：
Hilbert-Wolf, Hannah;Roberts, Eric;Downie, Bob;Mtelela, Cassy;Stevens, Nancy J.;O'Connor, Patrick
通讯作者：
O'Connor, Patrick
东非低岩浆输入地区的裂谷演化
影响因子：
5.3
作者：
Muirhead, James D.;Wright, Lachlan J.M.;Scholz, Christopher A.
通讯作者：
Scholz, Christopher A.