A. Adi Martha1 , T. Suroyo1 , T. Ismoyo1 , D. Damayanti1
1Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG), National Seismological Center, Jakarta, Indonesia
Information on the magnitude of the effect of earthquakes on the affected area is very important for disaster mitigation. Besides earthquake magnitude parameters, geological information and rock density also determine the earthquake effects. In lower density areas the effects of the earthquake were observed to get larger. The simple information on the structural conditions of a region can be obtained from the Bouguer anomaly map. To generate a Bouguer anomaly map which reflects the structure, we process FAA and elevation data obtained from the web http://topex.ucsd.edu/. We have analyzed some of the earthquakes using Bouguer anomaly information. The results show the same pattern of shake maps that are sourced from accelerograph data. Bouguer Anomaly region associated with the lower anomaly than the epicentral area can feel the effects in spite of having a relatively greater distance; this is because of the amplification effect experienced in rocks with low density (sediment). Higher Bouguer Anomaly region than the epicenter allow will not feel the effects of the earthquake were great despite being relatively close. This is because of the large damping effect of high density (igneous) rock.