Abra delta and northward continuation of Philippine Great Fault

Abstract

The Abra River of northwest Luzon appears to have built its delta into a fault trough that is located inside a shallow offshore bank, the latter continuing northwestward as a submerged ridge that dies out in Manila Trench. The faulted east margin of the bank is in line of continuation of the large Philippine Fault which crosses the Philippine Islands to the south. The Abra Delta front slope has close-spaced, relatively shallow submarine valleys cut into it as is usual of such slopes, and a turbidity current was discovered in one of these valleys.