Assessment of seismic hazard in the Erzincan (Turkey) region: construction of local velocity models and evaluation of potential ground motions

Abstract

The fundamental step in estimation of seismic damage and losses in urban areas is identification of regional potential seismic hazard. The accuracy of seismic analyses depends on the reliability of the local input parameters used in the corresponding hazard and loss models. This paper presents detailed seismic hazard analyses for an earthquake-prone region using locally derived source and site parameters. Main components of this study are construction of local seismic velocity models, probabilistic and deterministic seismic hazard analyses, and estimation of corresponding potential ground motions. The study area is Erzincan, which is a city on the eastern part of the North Anatolian Fault Zone. Located at a triple junction of major fault systems within a basin structure, Erzincan experienced major events (Ms ~8.0) in 1939 and (Mw = 6.6) in 1992. This study presents the first discussion in the literature on sitespecific probabilistic and deterministic hazard analyses for Erzincan. Using locally derived input parameters in site response modeling and hazard analyses, the earthquake potential of Erzincan is investigated in detail. Probabilistic seismic hazard analyses with a hybrid source model composed mainly of line sources show that for a return period of 475 years, the maximum peak ground acceleration value in the Erzincan city center is computed to be almost 1 g. On the other hand, probabilistic hazard analyses with only area sources yield ground motion amplitudes that are almost half of those obtained by the hybrid model. The deterministic hazard analyses also show that peak ground acceleration in the city center for a scenario event of Mw = 7.0 reaches 1.25 g at a soft soil site located at 2 km in distance from the fault plane. In summary, numerical results obtained with locally derived input parameters indicate that Erzincan has significant potential for hazard in terms of both local earthquake occurrence and site amplifications.

Seismological and Engineering Demand Misfits for Evaluating Simulated Ground Motion Records

“…In this study, three past earthquakes which occurred in regions with different geological characteristics are considered: The 1992 Erzincan-Turkey, the 1999 Duzce-Turkey and the 2009 L'Aquila-Italy events with corresponding magnitudes of 6.6, 7.1 and 6.3, respectively. Simulated records have been generated and verified by previous studies [24,[45][46][47] using the stochastic finite-fault simulation method based on a dynamic corner frequency approach as introduced by Motazedian and Atkinson [22]. This approach is an extension of the stochastic point-source method which considers contribution of the source, propagation and path effects.…”

“…This earthquake led to at least five hundred mortalities besides an economical damage cost of five to ten trillion Turkish Liras [50]. Erzincan is an area placed on a deep alluvial basin with softer soil conditions [47]. The region is formed at the conjunction of three active faults with strike-slip mechanisms: the left-lateral North East Anatolian, the right-lateral North Anatolian and the left-lateral Ovacik faults.…”

Blind study site assessment of shear-wave velocity at Kumamoto City, Japan, using direct-fitting SPAC methods

“…However, to accurately assess the physical effects related to local site conditions in surface ground motions, it is important to carefully estimate the structure deeper than the top 30 meters, preferably down to the bedrock layer. Particularly for deterministic hazard assessments which require analyses beyond empirical ground motion models, information on deeper structure via 1D, 2D or even 3D velocity models at sites or regions of interest become crucial (e.g., Magistrale et al 2000;Asten et al, 2014;Askan et al, 2015). The backbone to multi-dimensional models is 1D pro les well-resolved both spatially and depth-wise.…”

Evaluation of seismic performance measures for MDOF RC structures subjected to simulated and real ground motions

“…Simulations have recently been of particular interest in earthquake engineering as they can practically reflect the physics of earthquakes, the faulting mechanisms and the regional seismic parameters (e.g. : [11][12][13][14][15]). Recent studies reveal that the characteristics of input ground motions can affect engineering demand parameters.…”