Towards better design and management of tsunami evacuation routes: A case study of Ao Jak Beach Road

Abstract

Among the thousands of people killed or reported missing in Thailand during the 2004 Indian Ocean Tsunami were villagers in small communities on the Andaman Coast. A combination of factors contributed to loss of life, including the lack of defined evacuation routes. This vulnerability to tsunami attacks has recently been addressed with the demarcation of evacuation routes, along both well-maintained arteries and native surface (unpaved) roads. However, poor location design and irregular maintenance will reduce the lifetime that the latter can provide safe egress from remote coastlines. In this work we identified 10 major gullies and 18 landslides along a critical 0.5 km section of a tsunami evacuation road accessing a remote beach of the Andaman Coast in southern Thailand. Erosion rates from landslides and gullies approached 9500 Mg ha -1 in less than a year following widening of the road. Importantly, the degradation features, landslides in particular, reduced the effectiveness of the road to serve as a safe passageway to escape future tsunamis or large storm surges. This study demonstrates that greater attention should be given to appropriate road location, design and maintenance in integrated programmes aimed at reducing tsunami vulnerability in remote coastal areas, not only on the Andaman Coast, but worldwide. © The Geological Society of London 2012.