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In order to minimize the disaster risk caused by earthquakes, not only province and district-based studies, but also studies covering small areas such as neighborhoods and villages should be carried out. In this study, Abdurrahmangazi Neighborhood, one of the districts that was severely damaged by two earthquakes that took place on 23 October and 09 November 2011 in the province of Van, was examined. The building conditions and the ground conditions in the study area where the quarter is located have been considered together. Shear wave velocity (Vs) was used to determine the dynamic behavior of soils. The borehole data obtained in the study area were evaluated and the shear wave velocities were determined by using 5 different empirical relations developed by some researchers for the relationship between SPT-N and Vs . Using these, VS(30) values were determined and ground classifications were made according to the National Earthquake Hazard Reduction Program (NEHRP-2000), EUROCODE-8, the Regulation on Buildings to be Built in Earthquake Zones (DBYBHY-2007). In addition, the new earthquake regulations is Turkey Earthquake Building Regulations (TBDY-2018) were also considered. The building damage conditions and the ground conditions in the area where the quarter is located were evaluated together. It was determined that the building damages after earthquakes were caused by structural deficiencies and building quality for this neighborhood, regardless of the ground conditions, and damage distributions were interpreted accordingly.

Soil liquefaction is one of the ground deformations occurred during an earthquake which may cause serious damages such as settlement and tilting of structures due to loss of bearing capacity of foundations. Düzce and its surrounding settle on a plain which consists of silty and sandy layers with shallow groundwater level. Besides, the North Anatolian Fault Zone is a major seismic source which is capable of producing large magnitude earthquakes. All these data point out that the ground deformations like liquefaction and lateral spreading may occur during a probable large earthquake around Düzce and its close vicinity. In this study, the geotechnical data of 40 boreholes drilled to determine the local ground conditions and the groundwater level in Düzce were considered. Based on the field studies, it was aimed to evaluate the liquefaction potential considering the fact that the groundwater level is shallow as well as the subsurface soil is composed of loose alluvium. Liquefaction Potential Index (LPI) and Liquefaction Severity Index (LSI) methods were taken into account and the liquefaction potential of Düzce province was determined and mapped with respect to various earthquake scenarios in GIS environment. These maps are compared on the basis of different scenarios. Accordingly, it is concluded that the liquefaction potential is high-very high in the south and south-eastern sections of the study area where the construction of new residential buildings progressively continues. © 2019 Jeoloji Muhendisligi Dergisi. All rights reserved.

Funding text Bu çalışma, UDAP-G-16-03numaralı proje ile Afet ve Acil Durum Yönetimi (AFAD) Bakanlığınnca desteklenmiştir. Projeyi destekleyen ilgili kuruma teşekkür ederiz. Bununla birlikte AFAD, Planlama ve Risk Azaltma Dairesi Başkanlığından da H. Gürhan Ülgen ve Ahmet Demire teşekkürlerimizi sunarız. Rockfall ditches or areas can be constructed in order to protect against rockfalls in settlements that are in danger of rockfalls when the population density is not high. Nevertheless, in the design of such protection structures, essential site-specific engineering studies and analyzes are often not carried out appropriately. Therefore, rockfallditches are occasionally not capable of preventing rockfalls. Within the scope of this study, the performance of a 2 m-deep and 1 km-long rockfall ditch excavated at the upper elevation of touristic Akköy (Ürgüp) settlement in 2012 in order to prevent the entrance of falling rocks to the residential area was evaluated on the basis of 3-dimensional rockfall analyses. According to the rockfall risk classification, the settlement is under moderate rockfall risk. The digital surface model used in 3-dimensional rockfall analyses was generated by point cloud data obtained from photogrammetric images taken by unmanned aerial vehicle. During field observations, it was determined that the dimension of the previously fallen ignimbrite blocks could reach up to 2 m. On the other hand, the high persistency of discontinuities in the source zone indicates that the dimensions of the potential rockfall blocks may be large. As a result of the 3-dimensional rockfall analyses carried out in RocPro3D software, it was defined that the falling blocks are generally caught by the ditch excavated between the source zone and the settlement, but in some sections of the ditch those blocks may continue to roll over the rockfall ditch. Eventually, Akköy settlement is still partially under the danger of rockfalls. If the rockfall ditch is not periodically cleaned in the course of time, the extent of danger will enlarge with the decrease in the capacity of the trench. © 2019, TMMOB - Jeoloji Muhendisleri Odasi. All rights reserved.