Seismic hazard mitigation in developing countries is critical since even moderate earthquakes adversely affect many lives. On March 6, 2007, a magnitude 6.3 earthquake hit the Indonesian island of Sumatra. This moderate event caused 70 fatalities and 500 casualties, caused 130,000 displaced people, and severe damage or collapse of nearly 15,000 buildings. The total damage from the earthquake is estimated at over $180 million, which is a very large sum for this area. Indonesia, the world’s largest archipelago, is prone to earthquakes due to its location on the Pacific “Ring of Fire”. In December 2004, a large earthquake with a magnitude of 9.0 off Sumatra triggered a tsunami that killed over 230,000 people in a dozen Indian Ocean countries, including over 160,000 in Indonesia alone. The reconstruction effort in Sumatra has been slow. Shortly after the 2007 West Sumatra Earthquake, the Indonesian government invited the authors to survey the damage. The investigators found widespread damage to commercial, residential, and public buildings, and bridges. The majority of damaged buildings used unreinforced masonry (URM) walls and non-ductile concrete frames to resist lateral loading. The extensive damage is attributed to the engineering details and construction quality. Cost-effective, simple-to-implement engineering solutions to mitigate this type of damage in future events were proposed.
H. Kit Miyamoto and Amir S. Gilani
Miyamoto International, Inc., West Sacramento, CA, U.S.