Abstract
Short period spectral acceleration
S
s values and detailed contours are presented for seismic hazard assessment of Islamabad, Pakistan.
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► The seismic hazard of Islamabad is not uniform, and it varies from sector to sector. ► The F series of the sector is the most prone to seismic threat in Islamabad.
► S
s
at 0.2
s at a return period of 2500
years will enable to define seismic load. ►
S
1 at 1
s at return period of 2500
years will enable to define seismic load. ► Ninety percentages of the earthquakes in the Islamabad area are caused by the thrust fault mechanism.
Pakistan is prone to seismic activity, and its capital, Islamabad, is located close to the Main Boundary Thrust (MBT) fault. On October 8th, 2005 the disastrous Muzaffarabad earthquake shook Islamabad and damaged many high-rise buildings. A probabilistic seismic hazard analysis technique was used to estimate strong ground motion parameters for a closely spaced 1
km grid. Traditionally, PGA is calculated, which is then used in structural earthquake resistant design or seismic safety assessment. However, Peak Ground Acceleration (PGA) is not sufficient to design for seismic load or to account for the modern building code’s emphasis on the use of spectral acceleration values. Therefore, a seismic hazard analysis was performed for Islamabad, and the design parameters that are required by codes to account for seismic loading were derived.