法国斯特拉斯堡大学Frédéric Masson研究组取得一项新突破。他们提出了来自InSAR分析的北非努比亚-欧亚大陆斜向汇聚的地震蠕变和应变分配。这一研究成果于2025年2月5日发表在《地质学》杂志上。

研究人员表示，由于努比亚板块和欧亚板块之间的持续融合，北非地区面临着严重的地震和海啸危险。

利用雷达干涉测量（干涉合成孔径雷达，InSAR）分析，研究组提供了西经2°至东经11°区域内构造的震间行为约束，并绘制了第一张InSAR衍生的东西和垂直速度分量的区域比例尺图。尽管由于InSAR技术的固有局限性，N-S方向的运动尚未解决，但其毫米/年速度图揭示了沿着板块边界的三个不同的应变调节域。

在西泰尔，陆上和海上的褶皱和逆冲都能适应正面碰撞，定期产生大型逆冲地震，比如1981年的7.3级艾尔·阿斯南地震地震。在东泰尔，变形从撒哈拉地台到北部海岸线广泛分布。在中泰尔，研究团队确定了500公里长的Ghardimaou-北Constantine断层的主要地震行为，其特征是浅锁定深度（<5.1±0.5 km），并且是迄今为止用大地测量数据检测到的最慢（<2.5 mm/年）的大陆走滑断层之一。应变分区将斜向汇聚的大部分剪切分量转移到这个主要的内陆构造中，从而使近海逆冲断层和褶皱成为地震危险的主要来源。

附：英文原文

Title: Aseismic creep and strain partitioning accommodating the Nubia-Eurasia oblique convergence in northern Africa from InSAR analysis

Author: Renier Viltres, Cécile Doubre, Marie-Pierre Doin, Frédéric Masson

Issue&Volume: 2025-02-05

Abstract: The northern Africa region faces significant seismic and tsunami hazards, driven by the ongoing convergence between the Nubian and Eurasian plates. Using radar interferometry (interferometric synthetic aperture radar, InSAR) analysis, we provide constraints on the interseismic behavior of tectonic structures within the region between ～2°W and ～11°E using the first InSAR-derived regional-scale maps of east-west and vertical velocity components. Despite the unresolved N-Soriented motions due to inherent limitations to the InSAR technique, our millimeter-per-year level velocity maps reveal three distinct domains of strain accommodation along the plate boundary. In Western Tell, both onshore and offshore folds and thrusts accommodate frontal collision, regularly generating large reverse earthquakes, such as the Ms 7.3 El Asnam earthquake of 1981. In the Eastern Tell, deformation is widely distributed from the Saharan Platform to the northern coastlines. In the Central Tell, we identify the predominantly aseismic behavior of the 500-km-long Ghardimaou-North-Constantine fault, marked by a shallow locking depth (<5.1 ± 0.5 km) and standing out as one of the slowest (<2.5 mm/yr) continental strike-slip faults ever detected with geodetic data. Strain partitioning diverts most of the shear component of the oblique convergence into this major inland structure, thereby making the offshore thrusts and folds the principal sources of seismic hazard.

DOI: 10.1130/G53117.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G53117.1/651870/Aseismic-creep-and-strain-partitioning