International Journal of Engineering Research and General Science Volume 2, Issue 1, January 2014 ISSN 2091-2730 24 www.ijergs.org Probabilistic Seismic hazard Analysis of Kathmandu City, Nepal Samyog Shrestha 1 1 Scholar, Department of Civil Engineering, IOE Pulchock Campus, Tribhuwan University, Pulchock, Lalitpur, Nepal ABSTRACT -Kathmandu is classified as a highly earthquake prone city of Nepal. The center of Kathmandu City is located in the vicinity of ten independent seismic source zones which in reality are active faults. This creates uncertainties in the size, location and the rate of recurrence of earthquakes. Probabilistic seismic hazard analysis provides a framework in which these uncertainties can be identified, quantified and combined in a rational manner to provide a more complete picture of the seismic hazard. This study presents a PSHA of the center of Kathmandu city using the attenuation relationship given by Cornell et al (1979) in order to determine various levels of earthquake-caused ground motion that will be exceeded in a given future time period. KEYWORDS -Seismic source zone; active faults; recurrence of earthquakes; seismic hazard; attenuation relationship; earthquake- caused ground motion 1. INTRODUCTION Kathmandu city has been subjected to frequent earthquakes of moderate intensities and about once in a century to disastrous earthquake of higher magnitude. Earthquake was first recorded in Nepal on June 7, 1255 AD when one third of the total population in Kathmandu were killed by a 7.7 Richter scale. Magnitude-Frequency Data on Earthquakes in Nepal and the Surrounding Region (1911AD-1991AD) Earthquakes of magnitudes in Richter scale 5 to 6 6 to 7 7 to 7.5 7.5 to 8 >8 No. of events 41 17 10 2 1 Recurrence interval in years 2 5 8 40 81 Table 1: Earthquakes in Nepal (1911 to 1991) Recent earthquakes near Kathmandu city are shown in figure1 Figure 1: Recent earthquakes near Kathmandu