• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.04a
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• pp.52-57
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• 1998

Becaruse of the continual occurrence of minor and moderate earthquake in Korean peninsula, it is generally considered that Korean is nor located in safe region against probable earthquake and more, even though being recognized as a safe contry in earthquake. It is in particular noted that nowadays there has been much concern about undesirable disaster due to unexpected earthquake since the disaster of 1995 Kobe earthquake. Thus, the objective of this research is to develop appropriate design spectrum which could be practicably used in seismic design of important structures taking into consideration of local physical characteristics. Particularly, we have to keep in mind the lessons from 1985 Mexico earthquake which had disregarded deep research on local ground conditions, being a possible magnification phenomena of ground motions in weak soil layer. Various spectra has been described based on the analysis of historical earthquakes, and appropriate design spectrum has been proposed herein.

• Geomechanics and Engineering
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• v.31 no.1
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• pp.31-52
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• 2022

Investigating and evaluating the long-term creep behavior of historical buildings built on seismic zones is of great importance in terms of transferring these structures to future generations. Furthermore, assessing the earthquake behavior of historical structures such as masonry stone bridges is very important for the future and seismic safety of these structures. For this reason, in this study, earthquake analyses of a masonry stone bridge are carried out considering strong ground motions and various water levels. Tokatli masonry stone arch bridge that was built in the 10th century in Turkey-Karabük is selected for three-dimensional (3D) finite difference analyses and this bridge is modeled using FLAC3D software based on the three-dimensional finite difference method. Firstly, each stone element of the bridge is modeled separately and special stiffness parameters are defined between each stone element. Thanks to these parameters, the interaction conditions between each stone element are provided. Then, the Burger-Creep and Drucker-Prager material models are defined to arch material, rockfill material for evaluating the creep and seismic failure behaviors of the bridge. Besides, the boundaries of the 3D model of the bridge are modeled by considering the free-field and quiet boundary conditions, which were not considered in the past for the seismic behavior of masonry bridges. The bridge is analyzed for 6 different water levels and these water levels are 0 m, 30 m, 60 m, 70 m, 80 m, and 90 m, respectively. A total of 10 different seismic analyzes are performed and according to the seismic analysis results, it is concluded that historical stone bridges exhibit different seismic behaviors under different water levels. Moreover, it is openly seen that the water level is of great importance in terms of earthquake safety of historical stone bridges built in earthquake zones. For this reason, it is strongly recommended to consider the water levels while strengthening and analyzing the historical stone bridges.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.3 s.22
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• pp.1-8
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• 2006

The seismic zone factor is evaluated according to the regional characteristics of seismic response based on the historical and instrumental earthquake data. This study aims at arranging regional seismic characteristics by the analysis of earthquake data recorded in the Korean Peninsula and providing the fundamental data to be used for establishing seismic zone factor considering the domestic seismic characteristics. This paper provides the seismic characteristics in the Korean Peninsula according to the historical and instrumental records and then presents fundamental data for establishing seismic zone factors in domestic region.

• Structural Engineering and Mechanics
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• v.59 no.3
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• pp.539-558
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• 2016

Minarets are almost the inevitable part of Mosques in Islam and according to some, from a philosophical point of view, today they symbolize the spiritual elevation of man towards God. Due to slenderness, minarets are susceptible to earthquakes and wind loads. They are mostly built in a masonry style by using cut limestone blocks or occasionally by using bricks. In this study, one minaret (M1 Minaret) of one of the charmest mosques of Turkey, Sultan Ahmed Mosque, popularly known as Blue Mosque, built between 1609 and 1616 on the order of Sultan Ahmed by the architect Mehmet Agha is investigated under some registered earthquake loads. According to historical records, a great earthquake hit Istanbul and/or its close proximity approximately every 250 years. Ottomans tackled with the problem of building earthquake resistant, slender minarets by starting to use forged iron connectors with lead as a filler to fix them to the upper and lower and to adjacent stones instead of using traditional mortar only. Thus, the discrete stones are able to transfer tensile forces in some sense. This study investigates the contribution of lead to the energy absorption capacity of the minaret under extensive earthquakes occurred in the region. By using the software ANSYS/LS-DYNA in modelling and investigating the minaret nonlinearly, it is found out that under very big recorded earthquakes, the connectors of vertical cast iron-lead mechanism play very important role and help to keep the structure safe.

• Earthquakes and Structures
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• v.10 no.6
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• pp.1331-1346
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• 2016

Historical masonry structures have an important value for cultures and it is essential for every society to strengthen them and confidently transfer to the future. For this reason, determination of the seismic earthquake response, which is the most affecting factor to cause the damage at these structures, gain more importance. In this paper, the seismic earthquake behaviour of Kaya Çelebi Mosque, which is located in Turkey and the restoration process has still continued after 2011 Van earthquake, is determined. Firstly the dynamic modal analysis and subsequently the seismic spectral analysis are performed using the finite element model of the mosque constructed with restoration drawings in SAP2000 program. Maximum displacements, tensile, compressive and shear stresses are obtained and presented with contours diagrams. Turkish Earthquake Code and its general technical specifications are considered to evaluate the structural responses. After the analyses, it is seen that the displacements and compressive/shear stresses within the code limits. However, tension stresses exceeded the maximum values at some local regions. For this mosque, this is in tolerance limits considering the whole structure. But, it can be said that the tension stresses is very important for this type of the structures, especially between the stone and mortar. So, some additional strengthening solutions considering the originality of historical structures may be applicable on maximum tensile regions.

• The Korean Journal of Applied Statistics
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• v.35 no.1
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• pp.119-129
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• 2022

In this paper, we predict the earthquake magnitudes which were recently occurred in Gyeongju and Pohang, using statistical methods based on historical data. For this purpose, we use the five-year block maximum data of 1392~1771 period, which has a relatively high annual density, among the historical earthquake magnitude data of the Chosun Dynasty. Then, we present the prediction and analysis of earthquake magnitudes for the return level over return period in the Chosun Dynasty using the extreme value theory based on the distribution of generalized extreme values (GEV). We use maximum likelihood estimation (MLE) and L-moments estimation for parameters of GEV distribution. In particular, this study also demonstrates via the goodness-of-fit tests that the GEV distribution can be an appropriate analytical model for these historical earthquake magnitude data.

• Earthquakes and Structures
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• v.24 no.5
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• pp.377-391
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• 2023

The high seismic risk has once again revealed in Türkiye with two major earthquakes that occurred on 06.02.2023, which took its place among the most destructive earthquakes in the last century. Totally, 65 earthquakes that occurred in the historical period in Türkiye were taken into account within the scope of this study. The seismic parameters were compared by considering the last two earthquake hazard maps for the epicenters of these earthquakes. Earthquake Intensity (I) of historical earthquakes were converted to Peak Ground Acceleration (PGA) by using suggested relations. Structural analyzes were performed for a sample reinforced-concrete building by using the obtained PGA's and predicted PGA's in the last two earthquake hazard maps. In the structural analysis, two different material groups such as low (C12-S220) and normal (C25-S420) were selected. As the material strength increased, the period value decreased, while the seismic capacity and stiffness increased. It has been determined that there are differences between the measured and proposed seismic risks for some earthquakes, and as a result, there are significant differences between the expected target displacement values from the structures. Therefore, it will not be possible to estimate the damage and to determine the building performance realistically. The main purpose of the study is to reveal whether the earthquake risk is adequately represented on seismic and structural parameters.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.17-17
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• 2000

A magnitude of 7.3 in Richter scale earthquake the strongest in-land earthquake in hundred years struck central Taiwan on September 21, 1999. It caused over 2,400 deaths and 30 some trillion won losses. To give an overview of this devastating earthquake this presentation will cover the following topics: 1) Introduction to Taiwan historical and 921 earthquake. 2) Damages to people landslide building dam bridge tank power facility etc. 3) Strong motion data and its characteristics. 4) Some changes to the building code triggered by the experience of the earthquake. Finally a concluding remark will be made.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.93-101
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• 2005

Seismicity changes associated with foreshocks of large Korean historical earthquakes of MMI > VIII are investigated for earthquake prediction study. A number of tests showed that b-values of foreshocks associated with these large earthquakes are most stable for precursor period of 13 years before the earthquake and rectangular source area of $1.1^{\circ}$ by $1.1^{\circ}$ around the epicenter. The b-values of foreshocks for 11 large events of MMI > VIII for the above foreshock area and precursor period turns out to be smaller than the value of 0.36 for the whole historical earthquakes with average 0.27. Epicenters of these foreshocks of small b-values are distributed close to the location of the main large earthquake. These observations indicate a possibility of predicting large earthquakes by closely monitoring the change of b-value for an extended period over decades in the Korean peninsula.

• Journal of the Korean Geophysical Society
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• v.8 no.3
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• pp.115-121
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• 2005

Seismicity changes associated with foreshocks of large Korean historical earthquakes of MMI > VIII are investigated for earthquake prediction study. A number of tests showed that b-values of foreshocks associated with these large earthquakes are most stable for precursor period of 13 years before the earthquake and rectangular source area of 1.1o by 1.1o around the epicenter. The b-values of foreshocks for 11 large events of MMI > VIII for the above foreshock area and precursor period turns out to be smaller than the value of 0.36 for the whole historical earthquakes with average 0.27. Epicenters of these foreshocks of small b-values are distributed close to the location of the main large earthquake. These observations indicate a possibility of predicting large earthquakes by closely monitoring the change of b-value for an extended period over decades in the Korean peninsula.