NEOTECTONIC FAULT ACTIVITY IN HONG-KONG - EVIDENCE FROM SEISMIC EVENTS AND THERMOLUMINESCENCE DATING OF FAULT GOUGE

Hong Kong lies within a major NE-trending fault zone that has been rea ctivated during several tectonic episodes since the Palaeozoic. Three main faults sets are recognized in Hong Kong: a dominant NE-trending s et, an ENE-varying to E-trending set and a subordinate NW-trending set . Over the last 1000 years, within a distance of 350 km of Hong Kong, there have been about 40 earthquakes with magnitudes of over 4.75, and of these 11 had magnitudes of over 6.0. Microseismic events in the la st ten years are diffuse but may be associated with a major NE-trendin g fault and a fault intersection. Thermoluminescence (TL) dates of fau lt gouge suggest that there have been three episodes of recent fault a ctivity in Hong Kong; these occurred at approximately at 100 000, 190 000 and 270 000 years BP. TL dating of alluvial sediments also indicat es fault activity in the Late Pleistocene.