Presenter: Li, Kueimo
Date: 2015/11/26
Abstract
The collision of the Palawan microcontinental block (PCB) with the Philippine mobile belt (PMB) had significantly influenced the geological evolution of the Philippines.This is a interesting problme about what the PCBPMB boundary location where inside Mindoro island with varying from different geology and geophysical data. A late Early Miocene to early Middle Miocene age (20–16 Ma) is proposed for the major collision between the Palawan indenter and the Philippine mobile belt. With EHB and Global Centroid Moment Tensor catalogues, It is shown that following the southeasterly reduction of convergence rates from the Manila Trench offshore NW Mindoro to onshore SW Mindoro, the slab dipping angles steepen, were initiated at depth (~200 km) and propagate upwards. Observations of intermediatedepth earthquakes that exhibit predominantly downdip extensional stress patterns attest that the steepening of slab dipping angles is due to the negative buoyancy of the slab. In contrast, a broad region covered by central and south Mindoro, the Romblon group, and NW Panay, is characterized by a sporadic distribution of shallow earthquakes of mostly strikeslip type.
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