Seismic microzonation of soil amplification and liquefaction for Padang City

Adrin Tohari,S.-J. Hwang,L. Comfort,I.W. Segara,A. Hakam

doi:10.1051/e3sconf/202015602008

Abstract

The magnitude 7.6 MW earthquake that occurred on 30 September 2009 in West Sumatera caused significant damages to buildings in the city of Padang related to the phenomenon of amplification and liquefaction. This paper presents the results of the assessment and mapping of amplification and liquefaction, carried out in the coastal area of Padang City. Mapping of soil amplification was carried out in 250 locations using the HVSR microtremor method. Meanwhile, evaluation of the potential for liquefaction was carried out in 95 locations using a cone penetration test-based method. Based on the analysis, Padang City has five seismic susceptibility zonations. Coastal areas, including the sub-districts of Koto Tangah, North Padang, West Padang, and South Padang, are located in high to very high susceptibility to soil amplification and liquefaction. These results are in agreement with the phenomenon of building damage due to amplification and liquefaction during the 2009 earthquake.

Highlights

Large earthquakes can trigger tsunamis and liquefaction and ground shaking in coastal cities and cause damage to buildings and infrastructures built on soft soil layers even though they are far from the source of the earthquakes
This paper presents the results of the seismic microzonation study based on HVSR microtremor and cone penetration testing (CPT)-based liquefaction methods
According to the shape of the spectra, the horizontal to vertical spectrum ratio (H/V) spectra can be classified into three types: - Type A: H/V spectra with one distinct peak [Figure 5 (a)] - Type B: H/V spectra with two different peaks [Figures

Summary

Introduction

Large earthquakes can trigger tsunamis and liquefaction and ground shaking in coastal cities and cause damage to buildings and infrastructures built on soft soil layers even though they are far from the source of the earthquakes. Changes in material stiffness between bedrocks and soft soil layers can cause amplification of earthquake shakings, as observed during the 1995 Michoacan earthquake in Mexico City [1, 2]. Large earthquakes can trigger soil liquefaction, which can cause significant damage to buildings built on loose, water-saturated layers of sand. Damage losses due to liquefactions can reach more than ten billion dollars. The liquefaction disaster at the 1995 Kobe earthquake resulted in more than 11.8 billion dollars in damage to port and dock facilities [3]

Methods

Results

Conclusion