Daout S, Barbot S, Peltzer G, Doin M-P, Liu Z, Jolivet R
ISTerre Université Grenoble-Alpes, CNRS Grenoble France.
Earth Observatory of Singapore Nanyang Technological University Singapore.
Geophys Res Lett. 2016 Nov 16;43(21):11192-11201. doi: 10.1002/2016GL071061. Epub 2016 Nov 9.
Due to the limited resolution at depth of geodetic and other geophysical data, the geometry and the loading rate of the ramp-décollement faults below the metropolitan Los Angeles are poorly understood. Here we complement these data by assuming conservation of motion across the Big Bend of the San Andreas Fault. Using a Bayesian approach, we constrain the geometry of the ramp-décollement system from the Mojave block to Los Angeles and propose a partitioning of the convergence with 25.5 ± 0.5 mm/yr and 3.1 ± 0.6 mm/yr of strike-slip motion along the San Andreas Fault and the Whittier Fault, with 2.7 ± 0.9 mm/yr and 2.5 ± 1.0 mm/yr of updip movement along the Sierra Madre and the Puente Hills thrusts. Incorporating conservation of motion in geodetic models of strain accumulation reduces the number of free parameters and constitutes a useful methodology to estimate the tectonic loading and seismic potential of buried fault networks.
由于大地测量和其他地球物理数据在深度上的分辨率有限，人们对洛杉矶大都市下方缓坡 - 滑脱断层的几何形状和加载速率了解甚少。在此，我们通过假设圣安德烈亚斯断层大弯处的运动守恒来补充这些数据。我们采用贝叶斯方法，从莫哈韦地块到洛杉矶约束缓坡 - 滑脱系统的几何形状，并提出一种汇聚的划分方式，其中沿着圣安德烈亚斯断层和惠蒂尔断层的走滑运动速率分别为25.5±0.5毫米/年和3.1±0.6毫米/年，沿着圣盖博山和普恩特山逆冲断层的上倾运动速率分别为2.7±0.9毫米/年和2.5±1.0毫米/年。将运动守恒纳入应变积累的大地测量模型中，减少了自由参数的数量，并构成了一种估计埋藏断层网络构造载荷和地震潜力的有用方法。
