• Title/Summary/Keyword: Historical earthquakes

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Seismic vulnerability and preservation of historical masonry monumental structures

  • Dogangun, Adem;Sezen, Halil
    • Earthquakes and Structures
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    • v.3 no.1
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    • pp.83-95
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    • 2012
  • Seismic damage and vulnerability of five historical masonry structures surveyed after the 1999 Kocaeli and Duzce, Turkey earthquakes are discussed in this paper. The structures are located in two neighboring cities that have been struck by five very large ($M_s{\geq}7.0$) earthquakes during the $20^{th}$ century alone. Older masonry mosques with arches and domes and their masonry minarets (slender towers) were among the most affected structures in this highly seismic region. While some of the religious and historical structures had virtually no damage, most structures suffered significant damage or collapsed. In the city of Bolu, for example, approximately 600-year-old Imaret, 500-year-old Kadi, 250-year-old Sarachane, and 100-year-old Yildirim Bayezid mosques suffered substantial structural damage after the 1999 earthquakes. Another historical mosque surveyed in Duzce partially collapsed. Most common factors contributing to deterioration of historical structures are also presented. Furthermore, a brief overview of issues associated with analysis and modeling of historical masonry structures is provided.

Assessment of Historical Earthquake Magnitudes and Epicenters Using Ground Motion Simulations (지진동 모사를 통한 역사지진 규모와 진앙 평가)

  • Kim, Seongryong;Lee, Sang-Jun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.25 no.2
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    • pp.59-69
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    • 2021
  • Historical records of earthquakes are generally used as a basis to extrapolate the instrumental earthquake catalog in time and space during the probabilistic seismic hazard analysis (PSHA). However, the historical catalogs' input parameters determined through historical descriptions rather than any quantitative measurements are accompanied by considerable uncertainty in PSHA. Therefore, quantitative assessment to verify the historical earthquake parameters is essential for refining the reliability of PSHA. This study presents an approach and its application to constrain reliable ranges of the magnitude and corresponding epicenter of historical earthquakes. First, ranges rather than specific values of ground motion intensities are estimated at multiple locations with distances between each other for selected historical earthquakes by reviewing observed co-seismic natural phenomena, structural damage levels, or felt areas described in their historical records. Based on specific objective criteria, this study selects only one earthquake (July 24, 1643), which is potentially one of the largest historical earthquakes. Then, ground motion simulations are performed for sufficiently broadly distributed epicenters, with a regular grid to prevent one from relying on strong assumptions. Calculated peak ground accelerations and velocities in areas with the historical descriptions on corresponding earthquakes are converted to intensities with an empirical ground motion-intensity conversion equation to compare them with historical descriptions. For the ground motion simulation, ground motion prediction equations and a frequency-wavenumber method are used to consider the effects of possible source mechanisms and stress drop. From these quantitative calculations, reliable ranges of epicenters and magnitudes and the trade-off between them are inferred for the earthquake that can conservatively match the upper and lower boundaries of intensity values from historical descriptions.

A comparative analysis of seismic and structural parameters for historical period earthquakes in Türkiye

  • Ercan Isik
    • 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.

Determination of epicenters and magnitudes of future earthquakes based on the historical earthquake catalogues (역사지진 기록을 기초로한 지진규모와 위치 예측 방법)

  • 권오성;한상환
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2000.10a
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    • pp.323-330
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    • 2000
  • Three historical earthquake catalogues were compared with each other in the view of frequency of events per century, cumulative magnitude distribution, and annual earthquake occurrence rate in each unit grid of 0.1°by 0.1°. And, a method to determine earthquake epicenters and magnitudes was proposed given the historical earthquake data. With this method, the epicenters and magnitudes of future earthquakes in Korean penninsula for 1,000 years were generated with each earthquake catalogue. Earthquake PGAs with 10% exceedance probability in Seoul were calculated for each catalogue and compared.

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Some Characteristics of Seismicity and Stress State in the Korean Peninsula Using the Korean Seismic Data of the Past and the Present (과거 및 현재 지진 Data로부터 한반도 지진활동과 응력 상태)

  • 오충량;김소구;고복춘
    • The Journal of Engineering Geology
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    • v.5 no.3
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    • pp.309-329
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    • 1995
  • Seismicity and stress state in the Korean peninsula are studied using the catalogue of historical earthquakes and that from the seismological observations before the 1960s, with the aid of instrumental catalogue up to 1995. It seems that the completeness of the historical catalogue has a significant enhancement during the first two hundred years of the Yi dynasty, i.e., from the 1400s to the 1600s. From then on the catalogue may be regarded as near to complete for strong earthquakes in an overall sense. From the distribution of strong earthquakes, three seismic zones may be identified. From the south to the north, those are the southern seismic zone (남부지진대), the Seoul-Pyongyang seismic zone (서울-평양지진대), and the northern seismic zone (북부지진대). The mechanisms of some earthquakes obtained using first motion read- ings are reevaluated with a grid testing method. The results indicate that the compressional axis is nearly horizontal along the EW direction.

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Approach to the Earthquake Prediction by Analyzing Foreshocks of Large Korean Historical Earthquakes (역사지진에서 강진의 전진에 대한 특성 분석을 통한 지진 예지에 대한 고찰)

  • E, Sang-Hion;Lee, Kie-Hwa
    • 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.

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Approach to the Earthquake Prediction by Analyzing Foreshocks of Large Korean Historical Earthquakes (역사지진에서 강진의 전진에 대한 특성 분석을 통한 지진 예지에 대한 고찰)

  • E, Sang-Hion;Lee, Kie-Hwa
    • 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.

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Field investigation and seismic analysis of a historical brick masonry minaret damaged during the Van Earthquakes in 2011

  • Muvafik, Murat
    • Earthquakes and Structures
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    • v.6 no.5
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    • pp.457-472
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    • 2014
  • The paper presents the field investigations and seismic analyses of a historical masonry brick minaret damaged during October 23 (Erciş) and November 9 (Edremit), 2011 Van earthquakes in Turkey. Ulu Mosque Minaret located on Tebriz Kap1 Street in the city centre of Van, Turkey is selected for investigation. Two earthquakes hit the minaret within seventeen days, causing progressive damage. It was seen from the field investigations that the minaret was heavily damaged. To validate the field investigations, three dimensional finite element model of the minaret is constituted by ANSYS software using relievo drawings. Finite element model of the minaret is analyzed under the Van earthquake records to determine the seismic behavior. The displacements, maximum and minimum principal stresses and strains are obtained from the analyses and compared with field observations.

Investigation on seismic isolation retrofit of a historical masonry structure

  • Artar, Musa;Coban, Keziban;Yurdakul, Muhammet;Can, Omer;Yilmaz, Fatih;Yildiz, Mehmet B.
    • Earthquakes and Structures
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    • v.16 no.4
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    • pp.501-512
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    • 2019
  • In this study, seismic vulnerability assessment and seismic isolation retrofit of Bayburt Yakutiye Mosque is investigated. Bayburt Yakutiye Mosque was built in the early 19th century at about 30-meter distance to Coruh river in the center of Bayburt in Turkey. The walls of historical masonry structure were built with regional white and yellow stones and the domes of the mosque was built with masonry bricks. This study is completed in four basic phases. In first phase, experimental determination of the regional white stone used in the historical structure are investigated to determine mechanical properties as modulus of elasticity, poison ratio and compression strengths etc. The required information of the other materials such as masonry brick and the regional yellow stone are obtained from literature studies. In the second phase, three dimensional finite element model (FEM) of the historical masonry structure is prepared with 4738 shell elements and 24789 solid elements in SAP2000 software. In third phase, the vulnerability assessment of the historical mosque is researched under seismic loading such as Erzincan (13 March 1992), Kocaeli (17 August 1999) and Van (23 November 2011) earthquakes. In this phase, the locations where damage can occur are determined. In the final phase, rubber base isolators for seismic isolation retrofit is used in the macro model of historical masonry mosque to prevent the damage risk. The results of all analyses are comparatively evaluated in details and presented in tables and graphs. The results show that the application of rubber base isolators can prevent to occur the destructive effect of earthquakes.

Shaking Table Test of Full Scale Parapet Models for the Evaluation of Intensities of Historical Earthquakes (성첩 모델의 진동대 실험과 역사지진의 세기 평가)

  • 김재관
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2001.04a
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    • pp.461-467
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    • 2001
  • Shaking table tests were performed with full scale models of stone parapet on the ancient rampart. The objectives of these tests are to study the seismic behavior of the parapet and to obtain quantitative estimation of the intensities of historical earthquakes. Two test models were made based on the structure of the parapet remnant of a mountain fortress in Bukhan-San located in Seoul. Two types of infilling material are considered. The responses to models were tested subjected to three kinds of input motion.

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