Based on compiled data during the period 1779-2010, 48,000 earthquake events exceeding M4 had occurred in Indonesia. Since the earthquake data are available in various magnitude scales, we converted all scales into moment magnitude. By using the catalogs compiled, we constructed area earthquake source model and estimated the frequencymagnitude relationship. From recorded data by accelerometers installed at four stations in Padang, we plotted observed data on the several existing attenuation equations and selected a suitable attenuation relationship for Indonesia. Peak ground acceleration on 10% probability of exceedance in 50 years for rock and soft soil condition were calculated. We compared the expected acceleration with existing ones and discussed. Based on the expected acceleration calculated, we proposed design spectra in several major cities in Indonesia.

Probabilistic hazard estimate through out Nepal considering historical earthquakes, intra plate slip and faults are done. As a typical case probabilistic spectra are plotted for Pokhara city. For the city, design earthquakes for three probabilities of exceedences are simulated which can be useful to design new structures and retrofit of existing structures.

On April 25, 2015, a M w 7.8 earthquake struck the Gorkha district of Kathmandu, Nepal. In Patan, vibrational characteristics of a 300-year-old two-story masonry building near Patan Durbar Square had been measured prior the Gorkha earthquake. In the inspection of the building after the Gorkha earthquake, several new cracks were found. The vibrational characteristics of the building were measured again, and it was found that the natural frequencies after the earthquake were smaller than those before the earthquake, indicating the reduction of the stiffness. Finite element models of the structure representing pre-and post-earthquake conditions are established so that the natural frequencies match the pre-and post-earthquake measurements and the structural damage is identified based on the stiffness reduction. Finally, the dynamic analysis of the finite element model of the building in the pre-earthquake condition using the observed ground motion record during the Gorkha earthquake as the input is conducted, and the structural response of the building during the Gorkha earthquake is discussed.

Saving human lives and cultural heritage from natural disasters is a key to earthquake-disaster mitigation strategies. Culturally valued structures built before earthquake codes and regulations emerged are often vulnerable to earthquake loads, but such structures must be comprehensively studied before applying mitigation measures. Microtremor measurements in Patan Durbar Square area, a World Heritage site, were investigated to determine dynamic properties of the soil at four locations and the predominant ground frequency calculated to be 2.07 Hz. Ambient vibration in an old masonry building was measured and vibration frequencies in different modes were detected using the Fourier spectrum, which found that the building has fundamental period in transverse direction. The building’s damping was estimated to be 5.2-6.4%.

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