Seismic microzonation of soil amplification and liquefaction for Padang City

The magnitude 7.6 MW earthquake that occurred on 30 September 2009 in West Sumatera caused significant damages to buildings in the city of Padang related to the phenomenon of amplification and liquefaction. This paper presents the results of the assessment and mapping of amplification and liquefaction, carried out in the coastal area of Padang City. Mapping of soil amplification was carried out in 250 locations using the HVSR microtremor method. Meanwhile, evaluation of the potential for liquefaction was carried out in 95 locations using a cone penetration test-based method. Based on the analysis, Padang City has five seismic susceptibility zonations. Coastal areas, including the sub-districts of Koto Tangah, North Padang, West Padang, and South Padang, are located in high to very high susceptibility to soil amplification and liquefaction. These results are in agreement with the phenomenon of building damage due to amplification and liquefaction during the 2009 earthquake