Introduction

Inventory and Characterization of Landslides Induced by the 16 July 1990 Luzon, Philippine Earthquake
Ronaldo A. Arboleda and Ma. Theresa M. Regalado
Philippine Institute of Volcanology and Seismology

INTRODUCTION

The 16 July 1990 Luzon earthquake triggered and induced numerous landslides in northern and central Luzon, Philippines. Abundant landslides occurred northwest and west of the ground rupture along Digdig Fault and on a narrow zone closely following the rupture along the Philippine Fault Zone (Fig.1). Landslides were observed as far as Lagayan, Abra in the north; Agoo, La Union in the west and Dingalan, Aurora in the southeast. The landslide-affected region is part of the Luzon Central Cordillera Volcanic Belt and marks the junction of the southern end of the N-S trending Luzon Cordillera Mountain Range and the Caraballo Mountains. The uplifted mid tertiary volcano-tectonic complexes of the Luzon Cordillera Mountains join with the Pliocene-Pleistocene volcanic centers of the Caraballo Mountains to form a very rugged topography.

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