| Author | Zaman, Saeed |
| Call Number | AIT Diss no.ST-16-05 |
| Note | A dissertation submitted in partial fulfillment of the requirements for the
degree of Doctor of Engineering in
Structural Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Earthquakes are considered one of the most destructive and disruptive natural disasters. It causes serious threat to the life safety of people and to the economy of a country. In the past two decades several studies/attempts are made to develop probabilistic seismic hazard maps for Pakistan to limit the damaging effects associated with earthquake hazard. In the current study, a new probabilistic seismic hazard assessment (PSHA) of Pakistan has been carried out by using more comprehensive, state-of-the-art models of earthquake sources, GMPEs for different earthquake environments and logic tree technique to handle the epistemic uncertainties (while the past studies did not consider that). To get a detailed and updated understanding of the distribution and level of seismic hazard throughout the country, the current study comprises of three main objective which are: a) PSHA of Pakistan, b) PSH deaggregation for major cities of Pakistan and c) development of the first-order site-condition map of Pakistan and its integration with PSHA map. PSHA of Pakistan and PSH deaggregation for major cities of Pakistan has been carried out using National Seismic Hazard Maps (NSHM) USGS software with Frankel (1995) spatially smoothed-gridded seismicity approach. Spatially-smoothed gridded seismicity source models are developed to represent spatially distributed shallow, intermediate, and deep earthquakes in Pakistan and surrounding areas from a newly compiled instrumental earthquake catalogue. Active crustal faults with known slip rates from paleoseismic and global positioning system (GPS) studies are explicitly modeled as line sources. The Makran subduction zone in southern Pakistan is represented by a sloping rupture plane to make the source model realistic. To get a more accurate and complete picture of seismic hazard throughout Pakistan, the resulting PSHA maps are combined with the first-order site-condition map of Pakistan. The first-order site-condition map of Pakistan is developed by employing the Wald (2007)’s technique. The application and accuracy of this map is validated through 165 sites with VS30 measurements (directly available, from SPT N-values and from P-wave velocity values).
The obtained results include seismic hazard curves, uniform hazard spectra for major cities and maps of probabilistic peak ground acceleration (PGA) and spectral acceleration (SA). The maps are developed at various natural periods (0.2, 1.0, and 2.0s) for return periods of 475 and 2,475 years for bedrock site condition. Geographic hazard deaggregation results provide insight into what earthquake scenarios contribute most to the seismic hazard of each of major cities. The results showed that for both 475 and 2,475 years return periods, the seismic hazard at short-period structures (about 0.2 sec) is mostly dominated by moderate to large earthquakes from nearby seismic sources (either background or fault sources), while for long-period structures (1.0 sec or longer) seismic hazard is more contributed by distant large earthquakes. Furthermore based on first-order site-condition map of Pakistan, the design spectral response acceleration maps at 0.2 sec (???) and 1.0 sec (??1) are obtained in accordance with Section 11.4 of ASCE 7-05. These ??? and ??1 are the key parameters used in the determination of site-specific design response spectrum as well as for assigning the seismic design category (SDC) to a structure. |
| Year | 2017 |
| Type | Dissertation |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pennung Warnitchai; |
| Examination Committee(s) | Noppadol Phien-wej;Anwar, Naveed;Teraphan Ornthammarath;Adnan, Azlan Bin; |
| Scholarship Donor(s) | NWFP University of Engineering and Technology,Peshawa, Pakistan ;AIT Fellowship; |