TY - JOUR AU - Teuku Faisal Fathani, AU - Wahyu Wilopo, PY - 2017/01/20 Y2 - 2024/03/29 TI - SEISMIC MICROZONATION STUDIES CONSIDERING LOCAL SITE EFFECTS FOR YOGYAKARTA CITY, INDONESIA JF - GEOMATE Journal JA - INTERNATIONAL JOURNAL OF GEOMATE VL - 12 IS - 32 SE - Articles DO - UR - https://geomatejournal.com/geomate/article/view/1309 SP - 152-160 AB - <p>An Mw 6.3 earthquake hit Yogyakarta, Indonesia in 2006, causing massive damage in this <br>densely populated area. As a consequence, risk reduction efforts in terms of local seismic response and peak <br>ground acceleration (PGA) mapping is needed to improve the spatial planning and early assessment before<br>another disastrous earthquake. The determination of PGA for microzonation study was conducted by <br>referring to the Indonesian seismic code and empirical prediction by examining attenuation relationships <br>considering the local site effects. The site investigation was conducted at 87 locations, comprising 13 core <br>drillings and 74 microtremor measurements. Further, the nonlinear earthquake site response analyses were <br>conducted to calculate the local seismic response occurring in a layered soil. Referring to the seismic code<br>with a 2% probability of exceedance in 50 years and site characteristics, the maximum considered earthquake <br>geometric mean PGA for Yogyakarta City is 0.50-0.57g, while the southern area has higher PGA. The <br>empirical prediction by attenuation relationships that considers the 6.3 Mw Yogyakarta earthquake 2006 with <br>50-100 year return period resulted in PGA of 0.14g to 0.21g. Meanwhile, the empirical prediction based on <br>soil predominant period resulting from microtremor measurements shows that the southern part of the city<br>has higher PGA of 0.2g to 0.3g whereas the northern part has lower PGA of 0.1g to 0.2g. The result of <br>nonlinear earthquake site response analyses shows that the PGA at the southern part and the northern part of <br>the city have higher PGA up to 0.38g. The results show the significance of local site effects and site response <br>analysis in determining the earthquake characteristics in comparison to the present simplified empirical <br>approach.</p> ER -