Middle East (MIE)

Authors:

D. Giardini, L. Danciu, M. Erdik, K. Sesetyan, MB Demircioğlu, S. Akkar, L. Gulen, M. Zare, S. Adamia, A. Ansari, A. Arakelyan, A. Askan, M. Avanesyan, H. Babayan, T. Chelidze, R. Durgaryan, A. Elias, H. Hamzehloo, K. Hessami, D. Kalafat, O. Kale, A. Karakhanyan, MA. Khan, T. Mamadli, M. Al-Qarouti, M. Sayab, N. Tsereteli, M. Utkucu, O. Varazanashvili, M. Waseem, H. Yalçın, MT. Yılmaz

Summary

The Middle East (MIE) is covered by the hazard model developed within the 2014 Earthquake Model of the Middle East (EMME) Project. The model covers the following countries: Afghanistan, Armenia, Azerbaijan, Cyprus, Georgia, Iran, Jordan, Lebanon, Pakistan, Syria and Turkey (Danciu et al., 2016; Danciu et al., 2017; and Şeşetyan et al., 2018). The model was originally developed for the OpenQuake (OQ) engine. EMME products, data and results are available and documented through the web-platform of the European Facilities for Earthquake Hazard and Risk

Information about the OQ model versions and input files can be found on the Results and Dissemination page.

Interactive Viewer

The viewer below depicts the seismic sources and hazard results in terms of PGA for a return period of 475 years. Click on the menu in the upper right corner to select the layer.

viewer_legend

Tectonic overview

The Middle East region is highly seismically active, having > 100 MW > 7 earthquakes in ~1500 years. Most seismicity is due to complex convergence among the African, Arabian, Indian, and Eurasian tectonic plates. The region includes three subduction zones and a number of significant plate or block bounding faults. At the Hellenic and Cyprian subduction zones, the African plate subducts northward beneath the Anatolian block (convergence rate ~40 mm/yr), and the Makran subduction zone (~35 mm/yr) is the eastward extent of the Arabian-Eurasian plate contact. The continental Anatolian block is bounded to the north by the ~1500-km-long North Anatolian Fault (right-lateral motion and slip rate of ~24 mm/yr), and to the southeast by the East Anatolian fault (left-lateral motion and slip rate of ~9 mm/yr). Internally, the block exhibits "escape tectonics" in the form of normal faulting. The African and Arabian plates are separated by the Dead Sea Fault (left-lateral motion and slip rate of 2-8 mm/yr). Convergence between the Arabian and Eurasian plates (~20 mm/yr) is mostly accommodated by the Bitlis-Zagros fold and thrust belt. A number of other compressional and strike-slip structures are active within the continental crust of these plates. The eastern extent of the region is also subject to hazard from the Indo-Eurasian collision.

Basic Datasets

Seismic source zones were delineated and parametrised using a unified catalogue (Zare et al., 2014) and information about active faults (Gülen et al., 2014) as described in (Danciu et al., 2017). The ground motion logic tree was developed using strong-motion data (Akkar et al., 2014) as described in (Danciu et al., 2016).

Hazard Model

Seismic Source Characterisation

The development and characterisation of the seismic source model is described in Danciu et al. (2016). The source model incorporates information regarding tectonics, seismicity and faulting characteristics of the region.

Epistemic Uncertainties

The seismic source model consists of two independent source models: an area source model (Branch 1) and a fault source model combined with smoothed seismicity (Branch 2). Branch 1 and Branch 2 are combined using a logic tree, and assigned weights of 0.6 and 0.4, respectively.

  • Branch 1: Consists of 224 area sources based on seismicity patterns, tectonic setting, faults and other crustal structures, and in the absences of these data, historical earthquake evidence. These sources cover all tectonic regions (Figure 1).

  • Branch 2: Crustal seismicity is modelled using 778 simple faults with occurrence rates derived from fault slip rates, and point sources that model observed seismicity smoothed over a grid. Earthquakes with MW > 5.5 are modelled on the faults, and the Mmax of point sources in the proximity of faults are capped at this magnitude. Subduction interface seismicity is modelled using complex faults with occurrence rates derived from fault slip rates, and two alternative models delineating the subduction interfaces as complex faults were used. Subduction intraslab and deep seismicity are modelled by area sources (Figure 2).

The occurrence rates of all sources are modelled using a truncated exponential magnitude-frequency distribution, where Mmin = 4.0 and Mmax varies depending on the source typology.

mie_area_zones

Figure 1 - EMME area source model. From Danciu et al. (2017).

mie_area_zones

Figure 2 - EMME fault source and background seismicity model. From Danciu et al. (2017).

Ground Motion Characterisation

Table 1 shows the ground motion logic tree, consisting of a set of ground motion prediction equations (GMPEs) for each tectonic region: Active Shallow Crust, Stable Shallow Crust, Subduction Interface, Subduction Inslab, and Deep Seismicity.

Epistemic Uncertainties

For every tectonic region, epistemic uncertainty is considered by using multiple GMPEs, each with an associated logic tree weight.

Active Shallow Crust Weight
AkkarCagnan2010 0.2
AkkarEtAlRjb2014 0.35
ChiouYoungs2008 0.35
ZhaoEtAl2006Asc 0.1
Stable Shallow Crust Weight
AtkinsonBoore2006 0.4
ToroEtAl2002SHARE 0.25
Campbell2003SHARE 0.35
Subduction Interface Weight
AtkinsonBoore2003SInter 0.2
LinLee2008SInter 0.2
YoungsEtAl1997SInter 0.2
ZhaoEtAl2006SInter 0.4
Subduction Inslab Weight
AtkinsonBoore2003SSlab 0.2
LinLee2008SSlab 0.2
YoungsEtAl1997SSlab 0.2
ZhaoEtAl2006SSlab 0.4
Deep Seismicity Weight
LinLee2008SSlab 0.5
YoungsEtAl1997SSlab 0.5

Table 1 - GMPEs used in the MIE model.

Results

Hazard curves were computed with the OQ engine for peak ground acceleration (PGA) and spectral acceleration (SA) at 0.2s, 0.5s, 1.0s, and 2s. The computation was performed on a grid of 70614 sites (spaced at approximately 10 km) with reference soil conditions with shear wave velocity in the upper 30 meters (Vs30) of 760-800 m/s.

The hazard map for PGA corresponding to a 10% probability of exceedance in 50 years (475 year return period), can be seen using the interactive viewer. For a more comprehensive set of hazard and risk results, please see the GEM Visualization Tools.

References

Akkar S, Kale Ö, Ansari A, Durgaryan R, Askan Gündoğan A, Hamzehloo H, Harmandar E, Tsereteli N, Waseem M, Yazjeen T, Yılmaz MT (2014a) EMME strong-motion database serving for predictive model selection to EMME ground-motion logic-tree applications. In: Second European conference on earthquake engineering and seismology, İstanbul, Turkey, Abstract No. 3220

Danciu L, Kale Ö, Akkar S (2016) The 2014 Earthquake Model of the Middle East: ground motion model and uncertainties. Bull Earthq Eng (2016). doi:10.1007/s10518-016-9989-1

Danciu L, Şeşetyan K, Demircioglu M, Gülen L, Zare M, Basili R, et al. (2017) The 2014 Earthquake Model of the Middle East: seismogenic sources, Bulletin of Earthquake Engineering, doi:10.1007/s10518-017-0096-8

Gülen L, Şeşetyan K, Adamia S, Sadradze N, Gvencadze A, Karakhanyan A et al (2014) Earthquake model of the Middle East (EMME) project: active faults and seismic sources second European conference on earthquake engineering and seismology, 2ECEES, 24–29 Aug 2014, Istanbul, Turkey, Abstract No. 3216

Şeşetyan K, Danciu L, Demircioğlu M, Giardini D, Erdik M, Akkar S, Gülen L, Zare M et al. (2018) The 2014 Earthquake Model of the Middle East: overview and results. Bulletin of Earthquake Engineering (2018): 1-32. https://doi.org/10.1007/s10518-018-0346-4

Zare M, Amini H, Yazdi P, Sesetyan K, Demircioglu MB et al. (2014) Recent developments of the Middle East catalog. J Seismol 18(4):749–772