Observing seismic and silent faulting related to a megathrust earthquake cycle: Joint application of InSAR and creepmeter ground displacement measurements

大陆边缘的会聚板块边界属于地球上构造最活跃的地区，是毁灭性地震和海啸的潜在震源。虽然大部分应变积累发生沿着俯冲界面，在覆盖地壳的断层活动发生重大的危险变形。尽管智利北方有大量的地表断层活动的证据，但上板块断层活动与俯冲地震周期的各个阶段之间的关系在很大程度上还是未知的。在城市安托法加斯塔和阿里卡之间的地区，我们建议研究的位移速率和变形机制和地表响应的上板块之前，期间和之后的大地震。在野外用构造地貌学的方法研究过去的变形状态。该项目的核心是研究变形的持续状态，为此，我们将应用遥感和直接实地测量的方法。利用卫星雷达干涉测量（干涉合成孔径雷达），我们试图探测地面位移断层在厘米的分辨率。对于一个更精确的信号分析，我们建议使用蠕变计在选定的故障位置，以解决在亚毫米尺度的断层滑移的幅度和时间变化。这些方法的组合应允许调查各种尺度下的当前断层位移速率，并与长期地震周期进行比较。最终，我们希望开发一个综合模型，在智利前弧幕和永久应变积累。

Convergent plate boundaries at continental margins belong to the tectonically most active areas on earth and are the potential source of devastating earthquakes and tsunamis. While the bulk of strain accumulation occurs along the subduction interface, significant hazardous deformation occurs by fault activity in the overriding crust. Despite abundant evidence for surface faulting in northern Chile, it is largely unknown how upper plate faulting is related to stages of the subduction earthquake cycle. In the region between the cities Antofagasta and Arica, we propose to study the displacement rates and deformation mechanisms and surface response of the upper plate before, during and after large earthquakes. Past states of deformation will be studied by means of tectonic geomorphology in the field. The core of the project is then to study the ongoing state of deformation, for which we will apply methods of remote sensing and direct field measurements. Using satellite radar interferometry (InSAR) we attempt to detect ground displacements at faults at a resolution of centimetres. For an even more precise signal analysis we propose to use creepmeters at selected fault locations in order to resolve magnitude and temporal variability of fault slip at the submillimeter scale. The combination of these methods shall allow to investigate present fault displacement rates at various scales and to compare with the long term seismic cycle. Ultimately we want to develop an integrated model for episodic and permanent strain accumulation in the Chilean Forearc.