Study on correlativity among some seismological prediction indexes related to earthquake frequency or energy

Correlation among various seismological prediction indexes related to earthquake frequency N or energy E for describing seismicity changes is studied by seismic data of 11 seismic zones (areas) in the Sichuan-Yunnan region. A statistical test for correlativity shows that seismicity indexes obtained from transformation of earthquake frequency N or energy E have correlation to a certain extent while they are used to describe seismicity changes. If the transformation is linear in all cases, the correlation coefficient is equal to 1. The smaller the transformation deviation from linearity, the bigger the correlation coefficient is.

Availability of seismic vulnerability index(K_g) in the assessment of building damage in Van, Eastern Turkey

The seismic vulnerability index(Kg) is a parameter that depends on the dynamic properties of soil. With this parameter, it is possible to evaluate the vulnerability of a point-based site under strong ground motion. Since it is related to the natural vibration period and amplification factor, the parameter can be calculated for both soil and structure. In this study, HVSR microtremor measurements are recorded at more than 200 points in the Van region to generate a seismic vulnerability index map. After generating the map, it is determined that the hazard potential and seismic vulnerability index is high at the sites close to Van Lake and at the densely populated city center. Damage information of the buildings investigated after the 2011 Van earthquakes(Mw = 7.1) are placed on the seismic vulnerability index map and it is realized that there may be a correlation between the damage and the seismic vulnerability index. There is a high correlation, approximately 80 percent, between the damage rate map based on the damaged building data and the K_g values. In addition, vulnerability indexes of buildings are calculated and the effect of local soil conditions and building properties on the damage levels are determined. From the results of this study and the site observations after the 2011 Van earthquakes, it is found that structural damage is not only structure-dependent but is also related to the dynamic behavior of soil layers and local soil conditions.

A“Three-index”Seismic Performance Evaluation Method Based on Sino-US Seismic Code

The Code for Seismic Design of Buildings(GB50011-2010)in 2016 and the method of seismic performance-based design for high-rise buildings in the Guide for Performance-based Design of High-Rise Buildings(TBI2017)are compared.In view of the characteristics and limitations of the seismic performance index set by the Sino-US seismic code,a“three-index”performance index system and evaluation process considering the displacement angle of the structural interlayer,the plastic damage degree of components and the plastic strain of material is put forward;combining the example of time-history analysis of a out-of-code high-rise building under the rare earthquakes is verified.The results show that the method of seismic performance evaluation by using deformation control index in Sino-US seismic code is relatively simple;however,both are lacking in the setting of specific components and the whole structure level respectively.The"three-index"system can comprehensively and quantitatively evaluate the seismic performance of out-of-code high-rise buildings.

Study on the Remote Sensing Assessment of Seismic Intensity of the Yushu Earthquake Based on the Synthetic Seismic Damage Index

This paper provides an overview of the ideas and methods of the assessment of seismic intensity based on remote sensing and describes the models used to assess the remote sensing based synthetic seismic damage index and seismic intensity. With the data of damage information extracted from the high-resolution aerial images in the earthquake-stricken areas( Jiegu town,Yushu city,Qinghai) of the 2010 MS7. 1 Yushu earthquake,and the data obtained through post-earthquake field investigation,the seismic damage degree and seismic intensity have been estimated. The analysis of the results shows that the seismic intensity in Yushu city is estimated as IX through the RS assessment method,which is consistent with the result estimated according to the ground surveys. The results are discussed in the last part of the paper and indicate that the RS techniques are expected to be one of the main methods used to estimate the seismic intensity values in the emergency stage.

Indexes of CNPC Seismic Exploration in 1995

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Post-earthquake building damage assessment in Yushu using airborne SAR imagery

The synthetic aperture radar （SAR） plays an important role in earthquake emergency response because of its all-time and all-weather imaging capabilities. On April 14, 2010, an Ms7.1 earthquake occurred in Yushu county, Qinghai province of China, causing a lot of buildings collapsed. In this paper, the building damage in Yushu city due to the earthquake was assessed quantitatively using high-resolution X-band airborne SAR image. The features of the buildings with different damage levels （collapsed, partial collapsed, non-collapsed） in the SAR image were analyzed first. Based on these building features, we interpreted the individual building damage in Yushu city block by block and got the numbers of the collapsed, partial collapsed and non-collapsed buildings separately for each block, referring to pre-earthquake QuickBird image when necessary. Let the damage index of individual collapsed, partial collapsed, non-collapsed building be 1, 0.5, 0 respectively, the remote sensing damage index of each block was then calculated through remote sensing damage index equation. Finally, the preliminary quantitative relationship between the remote sensing damage index interpreted from the SAR image and that interpreted from the optical image was built up. It can be concluded that a desirable damage assessment result can be derived from high-resolution airborne SAR imagery.

Primary Quantitative Study on Earthquake Damage Extracted from Remote Sensing Imagery——A Case Study of Seismic Damage in the Urban Area of Dujiangyan due to the M_S8.0 Wenchuan Earthquake

The fast developing remote sensing techniques play an increasingly important role in earthquake emergency response, disaster survey and loss estimation. As there is a lack of quantitative studies on seismic damage based on remote sensing, its practicality in seismic disaster management has usually been questioned. The paper introduces the essential quantitative study idea, the concept of the remote sensing seismic damage index （D1RS） and analysis models, demonstrates the seismic damage indices （ D1G ） of buildings obtained from ground surveying and its quantitative relation to D1RS in Dujiangyan city, Sichuan Province, which was destroyed by the 2008 Wenchuan earthquake with Ms8.0. The primary results show that an obvious relationship exists between the D1RS of buildings obtained from the high resolution satellite or aerial remote sensing images and D1G or the building collapse ratio obtained through ground survey, which suggests that the quantitative study on seismic damage based on remote sensing will provide an effective method for seismic damage survey and loss estimation.

Seismic Hazard Matrix of Buildings in Yunnan

Seismologists have begun to investigate the earthquake damage and assess the economic losses on the spot in the Yunnan area since the earthquakes with M_S6.7 and M_S6.9 that occurred on the boundary between China and Myanmar west of Menglian county,Yunnan Province,on April 23,1992.From 1992 to 2003,50 destructive earthquakes occurred in Yunnan,and large amounts of data on seismic hazard have been accumulated.With focus on the major building structures,the paper makes statistical analysis on the earthquake damage ratio,loss ratio and seismic hazard index in the areas with different seismic intensity of the 50 events,and presents the seismic hazard matrix of buildings for the Yunnan area.

Site Effect Estimation Using Microtremor Measurements at New Luxor City Proposed Site, South Egypt*

The present study aims mainly at investigating the site effect at the new Luxor city, Egypt, using microtremor measurements. Accordingly, 41 ambient noise recordings were implemented covering the investigated area in a reasonable manner with spacing nearly 1 km between each measurement station. The data were analyzed using Nakamura’s technique. The results show that;the investigated area exhibits low fundamental frequency values ranging between 0.28 - 0.47 Hz and its corresponding amplification factor values vary between 2.3 and 6.8. Consequently, the studied site is characterized by the presence of thick soft sediments overlying a hard bed rock. The seismic vulnerability index (Kg) was estimated, relying on the estimated fundamental frequency (F0) and amplification factor (A0), through the range between 11 and 95 across the mapped area. The obtained Kg values were noticed to be compatible with amplification level results. The central part of the investigated area reflects the higher Kg and A0 values.