Landslides triggered by the Avaj, Iran earthquake of June 22, 2002

The 2002 Avaj, Iran earthquake (Mw = 6.5) triggered many landslides over an area of about 3600 km2. In this paper, we describe a ground-based field study conducted during several days immediately after the earthquake, and pre and post-earthquake landslide inventory maps that were prepared. The landslides due to earthquake include 47 fall and topple zones, 9 slides, and 3 lateral spreads. The largest slide is a rockslide (150 × 100 m), which occurred southeast of the village of Changureh. The main results of this study are:
• The density of earthquake triggered landslides decreases away from the fault zone in a manner that is asymmetric with respect to direction;
• Although several slides and lateral spreads were seen, the most common types of triggered landslides are falls and topples;
• The area throughout which landslides occurred, and maximum epicentral and fault zone distances of landslides, are comparable to similar data from other historical earthquakes;
• Landslides mostly occurred in the most susceptible geologic units, in which there were many landslides before the earthquake;
• New disrupted slides and falls generally occurred in ancient fall zones, but no information about reactivation of coherent slides is available.