Computational Investigation of Soil Liquefaction Susceptibility based on Standard Penetration Test Value of Miri District (Sarawak, Malaysia)

Miri is a district of Sarawak state of Malaysia and is a coastal area located at the boundary of Brunei. This paper deciphers the analysis of liquefaction susceptibility of the Miri district. Standard penetration test with N values (SPT-N) empirical criteria has been used for evaluating the liquefaction susceptibility in the Miri district. The software LiquefyPro and LiqIT have been used for the analysis by using the Idriss and Boulanger approach as this methodology encompass a simple technique and calculation. This exploration utilized a seismic tremor record from another area well-matched from target response spectrum with comparative qualities of Sarawak earthquake acquired from the Pacific Earthquake Engineering Research Center (PEER) online database (PEER NGA) with a moment magnitude of 6.0 and peak ground acceleration as 0.15 g on the ground surface. The ground motions assigned for assessment are predominantly attentive on a good complete match for the target response spectrum and on actual earthquakes that might happen in Sarawak. Liquefaction potential index (LPI), the factor of safety (Fs) and the probability of liquefaction (PL) for each soil layer was determined and then summed up for each borehole and were used to plot the contour maps by utilizing the geographical information system (GIS). From the results, the overall area of Miri is not liquefiable, only a few sites have liquefaction index as high, moreover, the obtained results of this study by using the methodology of Idriss and Boulanger are reliable. The results of this study can be used in seismic microzonation

Evaluation on the Soil Flexibility of the Largest HEP Dam Area in East Malaysia using 1-D Equivalent Linear Analysis

This paper presents the evaluation of soil flexibility at the vicinity of the Bakun HEP Dam, the largest in East Malaysia. The dam is located in the Belaga District of Sarawak, approximately 50 km from the active Tubau and Bukit Mersing fault lines. This area experienced earthquakes of magnitudes ranging between 3.5 and 5.4 during the period from 1994 and 2010. This study used global and local earthquake records to evaluate the site-specific seismic hazard using a 1-D equivalent linear analysis. SPT data from 15 boreholes are utilized. Soil flexibility, factor of safety, liquefaction probability and potential index are evaluated to find the ground settlement and soil liquefaction effects. The results show that the ground amplification of Belaga District is between 2.445 and 5.146, while the peak ground accelerations (PGA) at ground surface are at a maximum average of 0.25g PGA. The soil factors for Bakun District range from 2.6 - 3.0, for 2% POE in 50 years. This corresponds to a 2475-year return period. The response spectra are found matching with the target design response spectra for Sarawak as reported in the Malaysia National Annex (MS EN 1998-1:2015). The effects of soil liquefaction are found to be insignificant, as a result the nearby Bakun HEP dam is considered safe from any ground settlement. This study highlights the importance of evaluating the ability of new or existing structures in Belaga District to withstand up to 0.25g PGA in case any seismic event should occur in the future

Development of Systematic Land Use Planning Based on Seismic Microzonation: A Case Study on Miri district of Sarawak, Malaysia.

This study deals with the development of land-use planning based on seismic microzonation and it is a case study of Miri district of Sarawak, Malaysia. This study is timely for prevention of disaster, since Malaysia lies in the vicinity of regions (Sumatra, Indonesia, South Philippines and North Sulawesi) that have experienced strong earthquakes in the past. The main goal of this research is to develop the land-use planning map for future earthquakes to reduce the devastating effects of earthquake in the Miri district by utilizing the software geographical information system (ArcGIS). The highest peak ground acceleration of Sarawak is in Niah area of Miri district which is 0.15 g in terms of 10% probability of exceedance in 50 years corresponding to 2475 years return period. This research predominantly reports issues to provide the land-use planning of Miri district on the basis of seismic microzonation incorporated with site-specific ground response analysis and liquefaction susceptibility analysis. Seismic microzonation map was developed on the basis of seismic hazard assessment of Sarawak, geological and geotechnical aspects i.e. site response analysis and liquefaction susceptibility assessment by applying the analytical hierarchy process (AHP). 114 standard penetration test (SPT-N) boreholes were analysed across the Miri district. This study recognizes and inspects the factors in post-tremor land-use planning which can viably diminish the disastrous effects of earthquake in Miri district. Land-use is the main component to be utilized in this research. Processes and factors of land use administration planning is to clarify and analyze for the situation investigation of Miri district (Sarawak, Malaysia) to evaluate the applicability of land use management for earthquake calamity mitigation. From the results, it was found that the seismic hazard in the Miri district varies from low to high corresponding to 2475 years of return period with low to moderate as predominant over the Miri district. Only a few areas are under high hazard. Also, the land use planning map was compared with the current land use map acquired from satellite imagery and it was found that all built up is in the low hazard area. The “land-use planning” can be introduced in the Malaysian National Annex to Eurocode 8 (MNA-EC8) for the better planning of design of structures and the resistance of earthquakes

Response spectra for moderate seismic area - application to Miri district of Sarawak, Malaysia

The aim of this paper is to estimate the response spectra for moderate seismic area in Sarawak, Malaysia. In the present study, the response spectra for Miri district, in Sarawak, has been obtained by using 1-D equivalent linear site response analysis at 114 borehole locations. All the borehole sites are classified based on average shear wave velocity (Vs30) as per Malaysia National Annex to Eurocode 8 (MNA-EC8) site classifications using the geotechnical relationship. In this study, the input motion was selected from Pacific Earthquake Engineering Research (PEER-NGA) online database compatible with target response spectra of Sarawak at engineering bedrock by considering the seismic hazard map for 2475 years as return period and by following the 475 years return period as shown in (MNA-EC8). From the results of this study, it was found that the maximum response spectral acceleration (response spectra with 5% damping) is 2.25 g, 3.25 g and 1.7 g at the ground surface for MNA-EC8 site classes C, D and E respectively. It was also found that the results are under the provisions of seismic design code of Malaysia. The suggested results in this study can be used as a reference in Malaysia to support the MNA-EC8

A Framework of Systematic Land Use Vulnerability Modeling Based on Seismic Microzonation : A Case Study of Miri District of Sarawak, Malaysia

The objective of this research is to develop the framework for sustainable land-use planning on the basis of seismic microzonation to reduce the devastating effects of future earthquakes by utilizing the software geographical information system (ArcGIS). Miri district of Sarawak in Malaysia has been chosen as the study area because of having the highest peak ground acceleration which is 0.09g in terms of the 10% probability of exceedance in 50 years. In addition, the frequency of an earthquake with a magnitude up to 5.3 is approximately every 5-7 years. Therefore, it is vital to introduce land use planning in order to diminish the adverse effects of earthquakes in the future. For this purpose, Google Earth Pro was used for the collection of satellite image data for land use planning purposes. From the results, it was found that the seismic hazard in the Miri district varies from low to high corresponding to 2475 years of return period with low to moderate as predominant over the Miri district. Only a few areas are under high hazard. Also, the land use planning map was compared with the current land use map acquired from satellite imagery and it was found that all built-up is in the low hazard area. It is envisaged that the findings from this research will contribute immensely to the literature that will serve as background information and a guide for analysts, disaster management, engineering designers and seismologists in Malaysia and the world as a whole

Evaluation on the Soil Flexibility of the Largest HEP Dam Area in East Malaysia using 1-D Equivalent Linear Analysis

This paper presents the evaluation of soil flexibility at the vicinity of the Bakun HEP Dam, the largest in East Malaysia. The dam is located in the Belaga District of Sarawak, approximately 50 km from the active Tubau and Bukit Mersing fault lines. This area experienced earthquakes of magnitudes ranging between 3.5 and 5.4 during the period from 1994 and 2010. This study used global and local earthquake records to evaluate the site specific seismic hazard using a 1-D equivalent linear analysis. SPT data from 15 boreholes are utilized. Soil flexibility, factor of safety, liquefaction probability and potential index are evaluated to ascertain the ground settlement and soil liquefaction effects. The results show that the ground amplification of Belaga District is between 2.445 and 5.146, while the peak ground accelerations (PGA) at ground surface are at a maximum average of 0.25g PGA. The soil factors for Bakun District range from 2.6 - 3.0, for 2% POE in 50 years. This corresponds to a 2475 year return period. The response spectra are found matching with the target design response spectra for Sarawak as reported in the Malaysia National Annex (MS EN 1998-1:2015). The effects of soil liquefaction are found to be insignificant, as a result the nearby Bakun HEP dam is considered safe from any ground settlement. This study highlights the importance of evaluating the ability of new or existing structures in Belaga District to withstand up to 0.25g PGA in case any seismic event should occur in the future.