Fatma Nurten Sisman

In order to mitigate seismic risk in urban regions, the first task is to identify potential seismic losses in future earthquakes. Seismic loss estimation is an interdisciplinary framework including a wide range of contributions from geophysical and earthquake engineers, physical and economic planners to insurance companies. In this study, a moderate size city in Turkey, namely Erzincan, is modeled completely from geophysical attributes to the built environment. Erzincan city is on the eastern part of the North Anatolian Fault zone and it is located in the close vicinity of a triple conjunction of major fault systems within a basin structure. The city experienced two major events in the twentieth century; Ms8.0 in 1939 and Mw=6.6 in 1992. Hence as a study area, the city under concern has significant hazard potential. The main components of the study are probabilistic and deterministic seismic hazard assessment and estimation of potential ground motions, regional building fragility i...

Summary In this study, microtremor data are collected and interpreted at selected sites in the cities of Bolu and Duzce, both of which are located in major alluvial basins. SPAC method is used to estimate the one-dimensional Swave velocity profile at the BOL and DZC strong motion stations located in Bolu and Duzce, respectively. In this applicatin, we directly match the observed and modeled coherency spectra rather than inverting the observed dispersion curves for the phase velocities. Adding HVSR information, we have estimated velocity profiles of moderate Vs contrasts in soft Miocene and Eocene sediments at depths in the range 136-209 m, and at depths in the range 2000 to 2200 m.

The geology of the north-western Anatolia (Turkey) ranges from hard Mesozoic bedrock in mountainous areas to large sediment-filled, pull-apart basins formed by the North Anatolian Fault zone system. Düzce and Bolu city centres are located in major alluvial basins in the region, and both suffered from severe building damage during the 12 November 1999 Düzce earthquake (Mw = 7.2). In this study, a team consisting of geophysicists and civil engineers collected and interpreted passive array-based microtremor data in the cities of Bolu and Düzce, both of which are localities of urban development located on topographically flat, geologically young alluvial basins of Miocene age. Interpretation of the microtremor data under an assumption of dominant fundamental-mode Rayleigh-wave noise allowed derivation of the shear-wave velocity (Vs) profile. The depth of investigation was ~100 m from spatially-averaged coherency (SPAC) data alone. High-frequency microtremor array data to 25Hz allows res...

Risk mitigation in urban regions starts with identification of potential seismic losses in future earthquakes. Estimation of seismic losses concerns a wide range of authorities varying from geophysical and earthquake engineers, physical and economic planners to insurance companies while the process naturally involves inputs from multiple disciplines. In this study, we present a city-level model where potential seismic losses are expressed in terms of regional seismic hazard, local soil conditions and local building vulnerabilities. The main components of the study are probabilistic and deterministic seismic hazard assessment and estimation of potential ground motions, regional building vulnerability, fragility information, and loss functions. As the study area, Erzincan, a city on the eastern part of the North Anatolian Fault zone is selected. Located within a triple conjunction of major fault systems within a basin structure, and experienced two major events within the last century in 1939 (Ms=8.0) and in 1992 (Mw=6.6), this city has significant hazard potential. We present the results in terms of key components such as construction of a 2D velocity model, ground motion simulations of past earthquakes and scenario events, site-specific probabilistic seismic hazard analyses and fragility functions derived using regional building characteristics along with simulated regional ground motion data. The verification of the model is performed through comparisons of estimated mean damage ratios for the 1992 earthquake with the corresponding observed values. The consistency of the estimated and observed values points out the significance of using locally-derived models for every component of loss estimation process

Risk mitigation in urban regions starts with identification of potential seismic losses in future earthquakes. Estimation of seismic losses concerns a wide range of authorities varying from geophysical and earthquake engineers, physical and economic planners to insurance companies while the process naturally involves inputs from multiple disciplines. In this study, we present a city-level model where potential seismic losses are expressed in terms of regional seismic hazard, local soil conditions and local building vulnerabilities. The main components of the study are probabilistic and deterministic seismic hazard assessment and estimation of potential ground motions, regional building vulnerability, fragility information, and loss functions. As the study area, Erzincan, a city on the eastern part of the North Anatolian Fault zone is selected. Located within a triple conjunction of major fault systems within a basin structure, and experienced two major events within the last century...

The North Anatolian Fault Zone (NAFZ), the major tectonic structure in Turkey, is formed as a result of the relative motions between surrounding tectonic plates. The NAFZ is an active right lateral strikeslip fault located in Northern Anatolia. This fault, with an approximate total length of 1200 kilometers, starts at the Karliova triple junction in the East and extends west to the Aegean Sea. Combination of the tectonic and geological behavior of the region have led to destructive earthquakes with M ≥6.5 along NAFZ including the 1992 Erzincan (Mw=6.6), 1999 Kocaeli (7.4) and 1999 Düzce (7.2) events. These events occurred on soft soils located in mostly pull-apart basin and led to significant structural damages and human losses. Thus, it is essential to study the soil behavior in detail within urban areas along the NAFZ.

Kentsel alanlarda risk azaltma çalışmalarının ilk adımı incelenen bölgedeki potansiyel kayıpların belirlenmesidir. Sismik kayıpların saptanması, jeofizik mühendisliğinden sigorta sektörüne, deprem mühendisliğinden ekonomiye dek birçok farklı alanı ilgilendirmekte ve disiplinlerarası bir yaklaşım gerektirmektedir. Bu çalışmada, kentsel alanlarda kayıp tahmini için, sahaya-özel sismik tehlike analizleri, yapı kırılganlıkları ve kayıp modelleri içeren bir yaklaşım geliştirilmiştir. Bu çalışmanın temel bileşenleri çalışılan bölgeye ait yerel sismik hız modelleri, deterministik ve olasılıksal sismiktehlike analizleri, senaryo deprem simülasyonları, yapıstoğu özelliklerive kayıp fonksiyonlarıdır.Çalışma alanı olarak Kuzey Anadolu FayZonu’nun doğu kesimindeyer alan Erzincan bölgesiseçilmiştir.Üçönemli faysistemiarasındabir havzayapısı içerisinde yer alanve 1939ve 1992yıllarındayıkıcıdepremleryaşamış olanbu şehir,dikkate alınması gereken bir sismik tehlikeiçermektedir. Bu çalışmada 2012-201...