On the relationship between large earthquake and the extent of damage to buildings：2016 Meinong, Kaohsiung earthquake

Autor: Su-HuaChen, 陳素華
Rok vydání: 2017
Druh dokumentu: 學位論文 ; thesis
Popis: 105
SUMMARY We analyzed the Peak Ground Acceleration (PGA) distribution of the 2016 Meinong earthquake and we found that when the PGA reached 136cm/s² (equivalent to intensity 5) the houses encountered serious damages in the Tainan city. The actual damage situation of the disastrous area is not consistent with the PGA classification of the current seismic grading of the Central Weather Bureau, and the earthquake intensity of the disaster area can not be effectively quantified. The earthquake shaking time-span ranges from 10 to 13 seconds in the area of soil liquefaction in Annan, Central, Western, and North district of Tainan city, showing that the earthquake shaking time is related to the degree of liquefaction. The slightly damaged houses in the liquefied areas (the evaluation result not yet reach red and yellow risky threshold) mostly refers to RC structure, strengthening of reinforced brick buildings and other types of buildings. It shows that the impact factors of the building being damaged include not only the duration of earthquake shaking time, but also the type of the building and the seismic capacity. In addition, the result shows that the actual situation encountered in the disaster area is not consistent with the seismic grading content. Therefore, according to the seismic assessment method practiced in Japan, we propose a revised earthquake grading method suitable for Tainan area. Seismic classification should refer to the damage degree of building, earthquake shaking time-span, along with social and cultural changes for adjusting the PGA ranges and narrative content to provide readers with the concept of building safety during earthquake and the information of the loss from the property or life. INTRODUCTION The Meinong earthquake occurred at 3:57 in February 6, 2016, in Meinong, Kaohsiung, and it caused a tremendous disaster in Tainan region. In view of the frequent occurrence of earthquakes in Taiwan, we began to analyze the impact of the earthquake in the Tainan area, so as to reduce the disaster and work on the rescue plan in the future. MATERIALS AND METHODS Applied with seismic data from the Central Weather Bureau and the data of damage buildings in Tainan notified by the Emergency Operation Center, a total of 579 cases which include the red events (red sheet) and yellow events (yellow sheet), and the address of the points of light-damage which not yet meet red and yellow sheet standards. The station data and the building address damage notification are converted into the GMT software after computer program processing calculation to explore the impact of disaster points and seismic energy, to further explore the contents of the existing seismic classification system. RESULTS AND DISCUSSION According to the statistics of Tainan City Government, the Meinong Earthquake resulted in considerable damage of buildings and the soil liquefaction. After calculating the data of Central Weather Bureau and the damaged address of buildings, they were processed into the GMT software and got the 0206 earthquake PGA distribution, PGV distribution and duration of the earthquake. Comparison of the information showed that PGA was close to the actual disaster. Most of the buildings damaged by the earthquake were in accordance with the distribution of the energy from the east to the west where the intensity of the earthquake originates. The PGA was not consistent with the PGA of the Central Weather Bureau’s Seismic Intensity Grade Scale. In addition, the information of PGV displayed that the extent of damage to buildings was not obvious. The study also found that the longest duration of earthquake shaking were in Central and Western District, North District, Anping District, Southern District, Yongkang District, etc. ( Lasting up to 13 seconds.) There was soil liquefaction in these areas. It showed that the earthquake shaking time was highly correlated with soil liquefaction. Buildings with many minor damages were also in soil liquefied areas. This appearance displayed that soil liquefaction affected the damage of buildings. Therefore, regarding to the reasons for the destruction of buildings, we also need to consider the type of buildings and buildings seismic capacity. According to the above findings and evaluation method of Seismic Intensity in Japan, I suggest that the seismic intensity grade should be adjusted by the damage events and earthquake shaking time. In this way, we can provide readers to understand the specific extent of damage to the buildings directly. Based on the study of damaging buildings in earthquake disaster areas, there was differences between the content of Central Weather Bureau’s Seismic Intensity Grade Scale and the extent of the actual damage. It showed that the actual feelings of the people and the content of seismic intensity grade did not match. In my opinion, we should propose and adjust a new seismic intensity grade scale. This is only applicable in Tainan areas because the geology is different from everywhere. CONCLUSION While the energy of PGA reached 136 cm/s², buildings have been damaged seriously in the 2016 Meinong earthquake. Therefore, the PGA of the seismic intensity grade scale does not match with the real situation. The duration of the earthquake shaking affects the soil liquefaction and the degree of building-damaged. The contents of the current seismic intensity grade scale do not accord with the actual destructive experience of the disaster areas. I recommend that seismic grade system needs to be revised periodically. Furthermore, we should consider the actual situation of disaster areas and the duration of earthquake.
Databáze: Networked Digital Library of Theses & Dissertations
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