IS HONG KONG CAPABLE OF GENERATING MODERATE EARTHQUAKES? EVIDENCE FROM AMBIENT NOISE ADJOINT TOMOGRAPHY
Hong Kong, one of the most densely populated financial centers in the world, has long been considered as seismically quiet and free from seismic hazards. However, in history, Hong Kong was the center of several super volcanic eruptions during Yanshanian Movement. The legacy of these intense tectonic events may have left behind a major seismogenic structure within the core area of Hong Kong. We deployed 13 portable seismic nodal sensors to record 21 days of seismic records. Using ambient seismic noise adjoint tomography, we construct a high-resolution 3D shear wave velocity model of the upper crust beneath Hong Kong. We identified a locked segment in the northern Lantau Island Fault Zone constituted by broad fractured felsic rocks
(low velocity) and deep, rigid mafic intrusions (high shear rigidity). Modern seismic records confirm the presence of strain accumulation in this region. Our findings suggest that this structure has the potential to generate moderate earthquakes under tectonic stress, thus monitoring the fault motion in the Lantau Island area is necessary.
For additional information, please contact Mr. LI Zhanwen, lizhw95@connect.hku.hk.