Ground Acceleration Values Research Articles

Investigation of Earthquake Disaster Risk Using ArcGis Satellite Imagery Study Case in North Tapanuli Regency

Abstract Earthquakes are one of the natural phenomena that occur surprisingly without any signs or symptoms that can be felt by humans, so that generally earthquakes cause tremendous panic. Tectonic earthquakes from faults generate a Peak Ground Acceleration (PGA) value, which helps assess their risk impact. North Tapanuli Regency is one of the districts in Indonesia that is passed by two faults, namely Renun and Toru. To determine the risk of earthquake disasters in the area, calculations are carried out using spatial methods to obtain values of PGA, Mmax, and Tmax values. From the processing results, it is known that the maximum magnitude of the Toru segment is 7.37 M and the Renun segment is 7.69 M, and the Toru segment has a maximum earthquake return period in the Toru segment of 429 years and the renun segment has a return period of 1013 years. Also, a disaster mitigation map is obtained that is formed using the PGA value as a parameter, with an explanation that areas that have a higher PGA value (colored red) have a greater risk of being affected by an earthquake.

Assessment of seismic liquefaction hazard and ground response in subduction zone: A 1D non-linear effective stress approach

Abstract The Makran Subduction Zone (MSZ) represents a convergent plate boundary where the Arabian Plate is subducting beneath the Eurasian Plate. This study assessed liquefaction susceptibility and ground response in Gwadar region, located on the eastern side of MSZ. A comprehensive dataset of seismic records, compatible with Pakistan design code BCP: 2021 rock spectrum, was used as input motions at bedrock. A series of one-dimensional (ID) non-linear effective stress analyses (NL-ESA) was conducted using DEEPSOIL v7 numerical tool. The findings revealed that pore water pressure ratio (ru) exceeded the threshold value for liquefaction onset (ru > 0.8) at various depths within the site profiles. A significant de-amplification of peak ground acceleration values was observed at liquefiable depths in soft soils. The liquefied stratum exhibited a non-linear response, with high shear strain values manifesting plastic deformations. A comparison of computed design spectra with code spectra revealed significant discrepancies. It is demonstrated that BCP: 2021 underestimated site amplification for site class D profiles in the 0.1 to 0.8 s period range, while overestimating it for site class E profiles across the entire period range up to 1.6 s. The findings will benefit infrastructure development in the region, particularly within the China-Pakistan Economic Corridor.

Duration Models for Subduction Earthquakes

ABSTRACT An empirical model for the significant duration of acceleration for subduction zone earthquakes is developed based on the normalized Arias intensity. The data set is a subset from the Next Generation Attenuation-Subduction database (Bozorgnia and Stewart, 2020). The functional form of the duration model uses an additive model for the source, path, and site terms with three lognormally distributed random effects for the source, path, and site. The remaining aleatory variability is modeled by a power-normal distribution. There are two parts of the duration model: a model for the D5–75 duration and a model for the D5–X/D5–75 ratio, which can be combined with the D5–75 model to estimate the DY–X for any interval. The D5–75 model includes regionalized coefficients for Japan, New Zealand, South America, and Taiwan. The large-magnitude (M >7) scaling of the D5–75 model is much weaker than the recent duration model by Bahrampouri et al. (2021). The residuals of the D5–75 model are negatively correlated with the lnPGA residuals with a correlation coefficient of −0.50 such that above-average peak ground acceleration values are associated with below-average duration values.

Stochastic Generation of Peak Ground Accelerations Based on Single Seismic Event Data for Safety Assessment of Structures

The Korean Peninsula, characterized by low-to-moderate seismicity, faces a shortage of strong ground motion records, posing challenges for the seismic safety assessment of critical infrastructures. Given the rarity of large-magnitude earthquakes, generating a variety of earthquakes with rational values of Peak Ground Acceleration (PGA) is essential for robust seismic fragility and risk analysis. To address this, a new stochastic approach is proposed to simulate artificial earthquakes at multiple source-to-site distances and derive the probability distribution of PGA based on recorded data from a single seismic event. Two key source parameters, seismic moment and corner frequency, are treated as random variables with a negative correlation, reflecting their uncertainties and dependence on source-to-site distance. The Monte Carlo simulation with copula sampling of the key source parameters generates Fourier spectra for artificial earthquakes, which are transformed into the time domain to yield PGA distributions at various distances. A comparison with recorded data shows that the proposed method effectively simulates ground motion intensities, with no statistically significant differences between the simulated results and recorded data (p>0.05). The present method of determining PGA distributions provides a robust framework to enhance seismic risk analysis for the safety assessment of structures.

MODIFICATION OF THE ATTENUATION EQUATION FOR PEAK GROUND ACCELERATION (PGA) IN THE NORTH SUMATERA REGION

Prediction of the empirical formula for ground acceleration is an important thing to analyze for seismic estimation in an area. This needs to be done to reduce the negative impact of earthquakes as a more appropriate mitigation effort in planning and designing earthquake-resistant buildings. Therefore, the empirical formulation from Zhaou, et al is used, which is well adapted to the seismotectonic conditions of the North Sumatra region, which has high seismic vulnerability, considering that this region is located in an active subduction zone. This advantage allows the model to more accurately predict the maximum ground acceleration (PGA) produced by earthquakes in the region. The purpose of this research is to obtain an empirical formulation of the maximum ground acceleration value based on seismic parameters such as distance, depth, and magnitude. It will also show the relationship between these parameters and the value of maximum ground acceleration or peak ground acceleration (PGA) in the North Sumatra region. This study modifies the empirical formulation of Zhao, et al data sourced from the Meteorology Climatology and Geophysics Agency (BMKG) of North Sumatra in 2017-2023 with a magnitude of 3 - 6 Mw. This research uses non-linear regression with the least squares method. The results of the analysis of the empirical formula produce the constant value sought a = 1.4703 b = -0.0025, c = 20.7441, d = 0.0196, e = 0.0015, S_SS = -2.0843, and S_SL = -0.0529. An empirical formula was obtained for the North Sumatra region based on the research results. This equation can be used on a scale of 3.0 - 6.0 Mw and a distance to the earthquake source between 0 - 300 km. The relationship between each parameter of this empirical formula is that the PGA value will increase with the magnitude, and the PGA value will decrease as the epicentre distance increases.

Dependence of horizontal PGA prediction on site conditions at critically short hypocentral distances: an analysis based on Japanese strong motion data

A fundamental element in seismic hazard assessment studies is the prediction of maximum values of ground accelerations. This is achieved through an attenuation relationship, also known as the ground motion prediction equation (GMPE). Seismic design of structures generally assumes the occurrence of a large earthquake on a nearby fault. The predictions from the GMPE are linked to the magnitude, distance, and local site conditions. Critical near‑fault ground motions have unique characteristics such as magnitude saturation and distance saturation. To investigate the impact of local site conditions in the near‑fault region, we analyzed the attenuation relations using the accelerations recorded in Japan by the Kiban Kyoshin network (KiK‑net) from 2000 to 2023. All events with a magnitude equal to or greater than 5.5, and with focal depth and epicentral distance less than 20 km, were considered. In this study, the hypocentral distance ranges from 5 to 23 km. Ordinary least squares regression analysis was conducted for the maximum horizontal vector of ground accelerations. The attenuation relation coefficients for horizontal vector peak ground acceleration were estimated using an effective distance and saturation effect. An additional independent term, the average shear wave velocity of the soil to a depth of 30 meters below the ground surface, and more cost‑effective shallower depths were included in the regression model. The analysis revealed that the site condition is statistically non‑significant at very short hypocentral distances of less than 23 kilometers.

Comprehensive resilience assessment of bridge networks using ensemble learning method

The assessment of seismic resilience in bridge networks holds significant importance for urban disaster prevention and mitigation efforts. Unlike individual bridges, there has been limited efficiency in assessing bridge networks. A seismic resilience assessment methodology for bridge networks using ensemble learning methods is proposed in this paper. Initially, a comprehensive resilience index is proposed, integrating both structural and functional aspects of bridge networks. Using 3 ensemble learning methods, 9 parameters related to network structure and traffic characteristics are chosen as input variables for predicting the seismic resilience index. Finite element models of 18 bridges are constructed and combined to generate 3500 sets of virtual bridge networks for model training. The predictive accuracy of models trained using the 3 ensemble methods exceeds 89 %, and the expected values of peak ground acceleration (PGA) and functional loss rate are the most influential features. The methodology offers insights into the application of ensemble learning for bridge network seismic resilience assessment.

DEVELOPMENT OF PEAK GROUND ACCELERATION USING A NON-LINEAR APPROACH TO EVALUATE LIQUEFACTION POTENTIAL IN SEI WAMPU BRIDGE, LANGKAT, NORTH SUMATRA, INDONESIA

The design of building structures requires compliance with seismic codes and all their consequences. Based on geotechnical investigation reports, the construction of Sei Wampu Bridge in Langkat, North Sumatra, Indonesia, is located in an area where the soil layers are predominantly sand with shallow water levels because of its proximity to a river and is a high earthquake zone due to the Semangko fault. That condition will affect the potential of liquefaction occurring. This study aims to identify the liquefaction potential in the Sei Wampu Bridge. Based on Indonesian National Standard (SNI) 1726-2019, sites prone to liquefaction are categorized as site class-specific soil (F) and requires site-specific response analysis (SSRA) methods. Non-linear analysis 1-D is chosen to propagate earthquake waves with the software DEEPSOIL V7. The input parameter for soil movement utilizes an average spectral matching method with a minimum of 7 pairs of soil movement selected from the earthquake recording website, PEER Ground Motion Database. The selection of earthquake considers a 1000-year earthquake load return period, or a 7% probability exceeded within 75 years. Site-specific response analysis (SSRA) resulted in a peak ground acceleration (PGA) value for each borehole depth used in liquefaction potential analysis. Using a historical earthquake scenario with a 6.3 Mw shows that the research location has liquefaction potential at 0 m-15 m deep with high vulnerability levels, where the LPI value reaches 36.21.

Analisis Bahaya Bencana Gempa Bumi di Wilayah Kabupaten Pesisir Selatan

This study aims to determine the earthquake hazard levels in Pesisir Selatan Regency, West Sumatra Province, by identifying the Peak Ground Acceleration (PGA) values and the distribution of earthquake hazard levels. The type of research used is quantitative descriptive analysis and spatial analysis. The method employed in this study is Probabilistic Seismic Hazard Analysis (PSHA). To determine the Peak Ground Acceleration values, parameters such as earthquake location, occurrence time, and earthquake magnitude are used. For determining the earthquake hazard distribution, data on Ground Amplification Factor (GAF) is utilized. The results of this study show that the distribution of Peak Ground Acceleration in the study area ranges from 0.17 g to 0.93 g. The value of 0.17 g is found in Koto XI Tarusan District, while the highest value is observed in Silaut District. Additionally, the distribution of earthquake hazard levels shows that areas with low hazard level cover 697.04 km², moderate hazard level covers 4150.49 km², and high hazard level covers 1201.81 km². This study provides earthquake hazard maps that can be used for mitigation and planning in the region.

The Importance of seismic microzonation under the threat of an earthquake of the north anatolian fault in nilüfer, bursa, turkiye

The Nilüfer district experienced the most recent urbanization among the central districts of Bursa in South Marmara region with the completion of rapid construction. Since 358 BCE, many destructive earthquakes were reported on the branches of the North Anatolian Fault (NAF) which caused extensive damage to buildings and loss of life near Bursa city. Besides some studies conducted to define the soil behavior in the vicinity of Bursa, a seismic hazard study in Nilüfer is still lacking. We, therefore, carried out a microzonation study including the following steps. First, an earthquake hazard analysis was conducted and the peak ground acceleration (PGA) values were determined for an expected earthquake. In the next step, MASW (Multi-Channel Analysis of Surface Wave) measurements conducted at 54 points in 28 neighbourhoods of Nilüfer district were evaluated. Soil mechanical parameters were determined at 11 boreholes to assess the liquefaction potential. It was found that almost half of the study area suffers from low damage considering only the vulnerability index (Kg) index, which depends on the site effect. Therefore, in addition to the Kg values, we created a microzonation map using the results of soil liquefaction, settlement, changes in groundwater level, and the average values of spectral acceleration. The study area is classified by four damage levels changing from low to high. Using only the Kg index could not quantify the potential damage level in the study area, thus we showed that the districts of Altınşehir, Hippodrome, Ürünlü and Alaaddinbey, Ertuğrul, 29 Ekim, 23 Nisan, Ahmetyesevi and Minareliçavuş were identified at potentially high-risk damage zones. The results of this study clearly showed that considering the Kg index, which depends only on the local site effect, may lead to inadequate damage values.

Physical Characteristics Controlling Radiation from Heterogeneous Ruptures—Finite Faults

ABSTRACT Kinematic simulations of ground motion require representations of the earthquake source: the distribution of final slip, parameters of the source time function, and the velocity of rupture travel. There is a significant ambiguity in prescribing these physical characteristics, causing uncertainty in the resulting motions that needs to be quantified. The representation integral is an appropriate tool: it allows exact calculation of the source effect in both the near and far fields in the frequency band of practical interest. The commonly used distributions of slip have a k-square shape of their wavenumber spectra. Various k-square slips change the slope of the radiated spectra in the range of ∼−2.5 and −4.0 in both the far and near fields. The spectra generated by randomly disturbed constant slip are indistinguishable from those emitted by k-square faults. In both cases, variations in peak values of ground velocity and acceleration between realizations are relatively insignificant: under ∼15% for the same hypocenter position. The slopes of the Fourier spectra produced exclusively by the form of the slip function and the slip heterogeneity are equivalent to using a formal kappa filter with κ ranging from ∼0.025 to 0.045 s. No ad hoc high-frequency filtering (of kappa or fmax type) is required if fault finiteness is accounted for. Geometric irregularity of rupture fronts, at least for the way the front progression is randomized in our case, does not appreciably affect the slopes of the spectra. Its principal effect is in blurring the directivity, reducing the sharpness of radiated pulses. The most influential parameter affecting the peak ground motions for several commonly used slip functions is the maximum velocity of slip: scaling of vmax causes a proportional scaling in peak ground acceleration. This parameter is the most important to constrain to reduce ambiguities in predicted ground motions.

Probabilistic Seismic Hazard Assessment of the Southwestern Region of Saudi Arabia

In relation to its rapid infrastructure expansion, exemplified by projects like the Najran Valley Dam or the rehabilitation of agricultural terraces, Saudi Arabia stands out among the Arabian Gulf nations. To mitigate the earthquake-related risks effectively, it is imperative to conduct an exhaustive analysis of its natural hazards. The southwesternmost region of Saudi Arabia is the main subject area of this study for the probabilistic seismic hazard assessment (PSHA), which aims to identify the peak ground acceleration (PGA) and spectral acceleration (SA) values. The investigation encompasses a 10% and 5% probability of occurrence over a 50-year exposure time for both B/C and C NEHRP soils. In order to take into account the earthquake activity that takes place in the vicinity of the Red Sea Rift, which in fact may have an impact on the seismic hazard in this active tectonic region, different seismic source zones were especially designed for this evaluation. Various characteristics such as the uncertainties related to the b-value, the expected maximum magnitude, and different ground motion prediction equations (GMPEs) were integrated using a logic tree scheme. Additionally, regression relationships between the computed ground motion values were established, and a novel design response spectrum was developed and recommended for several cities. Regarding the key findings, it is significant to highlight that the seismic hazard decreases towards the northeast, when moving away from the Red Sea Rift, confirming anticipated trends where proximity to the rift corresponds to increased seismic hazard. Notably, cities such as Farasan Island, Jazan, Al Qunfundhah, Al Lith and Al Birk present the highest observed hazard values among all the cities analyzed. For these cities, the obtained maximum SA values for both 475 and 975 years under B/C site conditions are as follows: 0.268 g and 0.412 g, 0.121 g and 0.167 g, 0.099 g and 0.150 g, 0.083 g and 0.135 g, and 0.066 g and 0.118 g, respectively. These results emphasize the crucial necessity of adequately evaluating and thoroughly updating the seismic hazard inherent to these particular areas to enhance the risk reduction and disaster readiness initiatives.

Analisis Penggunaan Tanaman Vetiver terhadap Stabilitas Lereng pada Bendungan Way Sekampung

Problems that occur in the western part of As Way Sekampung have the potential for landslides to occur. Efforts used to handle slope strengthening by planting vetiver plants. The research method used to analyze slopes uses the limit equilibrium method on slip surface sections using the Morgenstren-Price method with the help of Geostudio 2023.1.0 software. SLOPE/W to get the safety factor under normal conditions and under seismic load conditions. By using a seismic load with a return period of 500 years (PE 10% in 50 years) with a Peak Ground Acceleration (PGA) value for the Way Sekampung Dam inundation area of 0,265 g. In vetiver plants, the root depth is simulated according to the top soil depth of 0,0 – 0,1 m. Soil planted with vetiver plants experienced an increase in the value of cohesion (c) by 74,42% and a decrease in the value of the angle of internal friction (φ˚) by 49,40%. The conclusion obtained was that slope stability in normal existing conditions was 4,525 and in normal vetiver plant strengthening conditions the safety factor increased to 4,529. Then, in the existing seismic conditions, the safety factor is 2,624 and in strengthening vetiver plants with seismic loads, the safety factor value increases to 2,626. It can be concluded that vetiver plants are able to strengthen slope conditions.

The effect of provincial policies on seismic disaster mitigation in China: An empirical study.

With the development of earthquake disaster reduction efforts in China, the content of earthquake disaster reduction policies has become increasingly enriched and improved. Particularly, multiple provincial governments have proposed earthquake disaster reduction planning policies. It is important to explore whether these policies can affect disaster mitigation. Therefore, this paper summarizes the earthquake disaster reduction plans and factors influencing seismic resilience. Panel data from 24 provinces between 2012 and 2021 were collected, and a difference-in-differences approach was used to construct an econometric model to evaluate the policy effects and analyze the enhancement of seismic resilience. The results show that the implementation of earthquake disaster reduction policies has a positive impact on earthquake monitoring, evacuation, and emergency relief capabilities, and the estimated policy effects are statistically significant. Moreover, a series of tests were conducted. The conclusions are as follows: (1) Earthquake disaster reduction policies have a positive impact on the improvement of seismic resilience in provinces. (2) Provinces with a higher number of earthquakes experience more significant effects from earthquake disaster reduction policies. (3) Provinces with higher seismic peak ground acceleration values exhibit more pronounced improvements in seismic resilience.

Analysis and Evaluation of Earthquake Hazard Zones Based on Spatial Models for Regency Regional Development Bantul

Abstract Earthquakes are a natural disaster that occur frequently in Indonesia. A region susceptible to earthquakes is the Bantul district. Buildings and infrastructure could be damaged by this disaster, especially in highly populated metropolitan areas where the Bantul Regency earthquake (Mw 6.4) on May 27, 2006, resulted in significant damage.The purpose of this research is to identify the distribution of the region’s level of stability against the possibility of an earthquake occurring, as well as the degree of compatibility between the vulnerability zone and the Development Territory Unit (SWP) of Bantul district. This research uses data collection techniques by direct observation with microtremors to calculate surface peak ground acceleration (PGA) with a value of Vs.30. The regional stability weighting matrix approach is used in this study, which is governed by Minister of Public Works Regulation Number 21 of 2007 covering Guidelines for Spatial Planning in Volcanic Eruptions and Earthquake-Prone Areas. The research results for Bantul Regency have a distribution of Vs.30 values between 175 - 350 m/s which is included in the Soft Rock (SC) category with surface peak ground acceleration (PGA) values between 0.112 g - 0.418 g. The final score for Bantul Regency is 20 - 43 which falls into the stable and less stable categories. The Development Area Unit (SWP) of Bantul Regency SWP, which is in the unstable zone, is dominantly distributed around the Opak Fault. SWP II, III, IV, and V require mitigation measures when used for residential areas. Spatial planning that is in accordance with built-up and non-built zones will be able to reduce risk factors.

Probabilistic Seismic Hazard Assessment of Sitamarhi near the Central Himalayan Region

ABSTRACT Sitamarhi, situated in the North-Bihar region of the Himalayan foothills is one of the seismically vulnerable regions of India. This region faced several devastating earthquakes, such as the 1934 and 1988 Bihar Nepal earthquake and the 2015 Nepal earthquake due to the movement of tectonic plates. The purpose of the present study is to exhibit the uniform hazard spectrum (UHS) and peak ground acceleration (PGA) values based on the probabilistic seismic hazard method using different seismotectonic parameters. The Gutenberg Richter (G-R) seismicity parameters ‘a’ and ‘b’ were estimated on the basis of regional earthquake magnitude data for the studied region. Regional earthquakes data were taken from the United States Geological Survey (USGS), International Seismological Centre (ISC), Indian Meteorological Department (IMD), and Seismotectonic Atlas of India. The region of interest for the probabilistic seismic hazard analysis (PSHA) is within a 500 km radius considering past seismicity and 62 seismotectonic sources which were identified in the study area. Large-scale geological features were utilised to describe the regional seismic source zones, which were used to derive the relationship between return period and ground motion parameters. Estimated PGA values are 0.92g for 2% and 0.68g for 10% probability of exceedance in 50 years time period, respectively. This research infer that the West Patna fault (WPF) and Sitamarhi fault (SMF) are the two maximum contributors in PGA for the Sitamarhi region.

Evaluation Of The Impact Of Liquefaction Potential On The Construction Of The Solo - Yogyakarta - NYIA Kulon Toll Road

Abstract The Solo - Yogyakarta - NYIA Kulon Progo Toll Road is one of the projects that aims to improve road network connectivity between Central Java and Yogyakarta. Liquefaction occurred in Yogyakarta after the 2006 earthquake, characterized by sand boiling and lateral spreading. This research was conducted to analyze the potential of liquefaction and evaluate the impacts that occur after liquefaction. The analysis of liquefaction potential uses the method developed by Idriss and Boulanger (2008), the maximum peak ground acceleration value using the earthquake return period of 100 years, 250 years, 1000 years, 2500 years, 5000 years, and 10000 years. Post-liquefaction analyses were conducted by calculating ground settlement developed by Yoshimine et al. (2006) and lateral displacement designed by Zhang (2004). The effect of liquefaction on bored pile foundations was assessed by comparing conditions without liquefaction and with liquefaction. The analysis showed 13 potential liquefaction borehole points with low - high liquefaction susceptibility levels. Post-liquefaction analysis shows that liquefaction can cause 0 cm - 27.32 cm settlement and lateral displacement of 0 cm - 199.24 cm.

Impact of Multiple Faults on the Maximum Credible Ground-Motion Parameters of Large Earthquakes at a Near-Field Site

The ground-motion simulation of regional-specific earthquake scenarios is crucial for the seismic design of key facilities. Herein, we considered parameter uncertainty in ground-motion simulations and the impact of multiple faults when determining the maximum credible ground-motion parameters of large earthquakes at a near-field dam. The source models of the Daju–Lijiang, Xiaozhongdian–Daju, and Longpan–Qiaohou faults were established based on geological and geophysical data. Although the method for identifying asperity is not yet mature and still faces many difficulties, it provides an opportunity to identify the non-uniform slip distribution on the rupture plane by earthquake scenarios. A multi-scheme stochastic finite-fault simulation method was then used to estimate the minimum; mean; maximum; and 50th-, 84th-, and 95th-percentile values of the peak ground acceleration and pseudo-spectral acceleration response spectra. The results showed that the Longpan–Qiaohou fault can generate the largest ground-motion parameters compared with the other two faults. Moreover, this result was supported by the statistical analysis of the results of twelve thousand simulations of these three faults. Thus, it can be concluded that the maximum credible ground-motion parameters are represented by the 84th-percentile pseudo-spectral acceleration response spectrum of the Longpan–Qiaohou fault. This finding will benefit the seismic safety design of the target dam. More importantly, this multi-scheme method can be applied to other key facilities to obtain reasonable ground-motion parameters.

Structural optimization design of multi ribbed composite wall of building components under seismic load based on random optimization algorithm and resilience model

The multi ribbed composite wall structure is also known as the multi ribbed wall panel light frame structure. This structure is suitable for housing construction in the residential field. The special structural failure process and mode of multi ribbed composite walls are different from traditional walls. To fully utilize the excellent structural performance in building construction and improve the seismic performance of the building, based on the transformation principle of subset optimization algorithm for optimization problems, a constrained subset simulation optimization algorithm suitable for optimizing the maximum displacement angle of multi ribbed composite wall panels is designed. The Bayesian algorithm is used to construct a restoring force model for multi ribbed composite wall panels. The constrained subset simulation optimization algorithm and resilience model are used to optimize the seismic performance of 4-layer multi ribbed composite wall panels. The results show that the section height and the equivalent slant support width of the continuous column for the 4-story multi ribbed composite wall panel change from discrete distribution to aggregation with the increase of iteration. Finally, the sampling is stable in the 9th floor. At this time, the section height of the continuous column is 230 mm, and the equivalent slant support width is 525. After optimization, the failure probability of both extreme displacement angle states has decreased. When the peak ground acceleration is 1.0 g, the optimized second limit state failure probability is less than 100%. When the peak ground acceleration value is between 0.2 g and 0.6 g, both limit states show a rapid upward trend. The constrained subset simulation optimization algorithm and Bayesian quantitative resilience model proposed in the research can effectively optimize the seismic performance of multi ribbed composite walls.

Preliminary study of liquefaction potential on the NYIA-Kulon Progo Toll Road Construction Project (Klaten Interchange STA 21+800 – 22+300)

Abstract The Solo-Jogja NYIA Kulon Progo toll road construction project section 1 package 1.1, which connects Kartasura to Klaten Regency. Based on the regional geological conditions, the Klaten interchange at STA 21+800-22+300 is situated in the Opak Merapi-Merbabu fault area predominantly composed of sandy lithology. Consequently, there is a potential for liquefaction when an earthquake occurs. This research analysis of liquefaction potential using a field test data approach, namely the SPT (Standard Penetration Test) was conducted to assess the seismic and subsurface conditions at Klaten Interchange STA 21+800 - 22+300. The seismic conditions at the Klaten interchange, located 6-7 km from the Opak fault, result in a Peak Ground Acceleration (PGA) value of 0.78 g, corresponding to class 5 on the BMKG MMI scale, potentially causing serious damage to buildings. The VS30 value in the research area ranges from 278.9 - 654.3 m/s, indicating a medium soil type. Subsurface conditions at STA 21+800-21+300 are divided into three zones based on the distance of each borehole. The SPT result shows that zone 1 is dominated by Silty Sand with Loose to Medium Dense consistency, zone 2 is dominated by Silty Sand to Sand with Medium Dense to Very Dense consistency, zone 3 is dominated by Silty Sand with a Medium Dense to Very Dense consistency. The results of the liquefaction potential calculation study indicate that several borehole points have the potential for liquefaction because the safety factor (FS) value is less than 1. Zone 1 has three points that have the potential for liquefaction: DBs-01, DBs-05, and DBs-07. Zone 2 includes two points with potential liquefaction: DBs-08 and DBs-09. Zone 3 has one point with potential for liquefaction: DBs-10.