Seismic Hazard Assessment of Northern Iraq

Ghassan I. Aleqabi & Hafidh A. A. Ghalib
Washington University in Saint Louis, Campus Box 1169, One Brookings Drive, Saint Louis, MO 63130, USA.
Array Information Technology, 5130 Commercial Drive, Suite B, Melbourne, FL 32940, USA.


Abstract 

Seismic hazard assessment is the estimation of the likelihood that an earthquake will
occur in a given geographic area, within a particular window of time, and that it develops
ground motion acceleration or intensity at a specific place within a specific area that
exceeds a given threshold. It can be used as a tool for rational planning and designing in
seismically active areas. For seismic hazard quantification, statistical analyzes of
earthquake catalogs of northern Iraq and surrounding regions are carried out to estimate
the rate and spatial distribution of earthquake events as a function of the magnitude and
geographical location. Most techniques for estimating the likelihood of occurrence
within a particular area are based on historical data of that region. An essential step in
characterizing seismic hazards in an area is to determine the frequency and location of
past earthquakes. Earthquakes tend to cluster around the most active faults. Kernel
density estimators using a Gaussian kernel are applied to assess seismic hazard in the
area. We performed Probabilistic Seismic Hazard Analysis (PSHA) to quantify the
probability of exceeding a given ground motion in the area. The highest probability of
seismic hazard exists in the northeastern part of Iraq and the Zagros regions. The
seismic hazard is lowest to the west and south of northern Iraq, in the Mesopotamian
valley. The comparison between the obtained results and the seismotectonic models of
Iraq reveals that the current distribution of regional earthquakes agrees with the
seismotectonic provinces of Iraq.

Key Words:
Seismic
Hazard
risk
probability
PSHA


References

[1] Lee, V. W., "On Strong Motion Uniform Risk Functionals Computed from General Probability
Distributions of Earthquake Recurrences", Int. Journal of Soil Dynamics and Earthquake Eng., Vol.
(11), No. (6), pp. 357-367. (1992).

[2] Abdulnaby, W., Mahdi, H., Numan, N., and Al-Shukri, H.”Seismotectonics of the Bitlis–Zagros Fold
and Thrust Belt in Northern Iraq and Surrounding Regions from Moment Tensor Analysis", Pure and
Applied Geophysics, Vol. (171), No. 7, pp. 1237-1250. (2014).

[3] Ghalib, H. A. A., Aleqabi, G. I., Ali, B. S., Saleh, B. I., Mahmood, D. S., Gupta. I. N., Wagner, R.
A. , Shore, P. J., Mahmood, A., Abdullah, S., Shaswar, O. K., Ibrahim, F., Ali, B., Omar, L.,
Aziz, N. I., Ahmed, N. H., Ali, A. A., Taqi, A.-K. A., and Khalaf , S. R.C.M.P. "Seismic
characteristics of northern Iraq and surrounding regions", in Proceedings of the 28th Seismic Research
Review: Ground-Based Nuclear Explosion Monitoring Technologies , LA-UR-06-5471, Vol. 1, pp.
40–48. (2006).

[4] Gutenberg, B. and Richter, C. F. "Seismicity of the Earth and Associated Phenomena", 2nd ed.,
Princeton Univ. Press, pp. 310. (1954).

[5] McGuire, R. K. "Seismic structural response risk analysis, incorporating peak response regressions on
earthquake magnitude and distance", Mass. Inst. Tech., Dept. of Civil Eng., Publication No. 399, p.
371. (1974).

[6] Cornell, C. A. "Engineering Seismic Risk Analysis", Bulletin of the Seismological Society of
America, Vol. (58), No. 5, pp. 1583-1606. (1968).

[7] McGuire, R. K."FORTRAN computer program for seismic risk analysis", U.S. Geol. Survey Open-
File Rep., 76-67, p.90. (1976).

[8] Wessel, P., and W. H. F. Smith, New, improved version of Generic Mapping Tools released, EOS
Trans. Amer. Geophys. U., vol. 79 (47), pp. 579, 1998.