Search Results (21)

Indonesia experiences some of the world’s highest seismic activity, making earthquakes a major source of physical, economic, and social losses. To better quantify these impacts, this study proposes a comprehensive evaluation framework with two new metrics: the Seismic Severity Index (SSI) and the Seismic Impact Index (SII). The indices are derived using four weighting methods—Grey Relational Analysis (GRA), Equal Weights, the Entropy Weight Method (EWM), and Criteria Importance Through Intercriteria Correlation (CRITIC)—and applied to 28 regencies and municipalities affected by damaging earthquakes from 2016 to 2022. Results show that the 2018 earthquake, intensified by a tsunami and liquefaction, caused the most severe losses. Palu Municipality and Donggala Regency consistently recorded high SSI values across all weighting schemes. The SII further identifies Sigi Regency, Donggala Regency, and Palu Municipality as the most heavily impacted areas, although rankings varied by method. Overall, Sigi Regency, Palu City, Donggala Regency, North Lombok, West Lombok and Cianjur exhibit the highest combined severity and impact, while Garut, Ciamis, and Cilacap experienced relatively minor effects. The study concludes that integrating GRA with EWM and CRITIC yields a robust earthquake loss index to support future disaster risk reduction policies. Full article

Rapid and accurate detection of primary waves (P-waves) using high-rate Global Navigation Satellite System (GNSS) data is essential for earthquake monitoring and tsunami early warning systems, where traditional seismic methods are less effective in noisy environments. We applied a wavelet-based method using a Mexican hat wavelet and dynamic threshold to thoroughly analyze the three-component displacement waveforms of the 2009 Padang, 2012 Simeulue, and 2018 Palu Indonesian earthquakes. Data from the Sumatran GPS Array and Indonesian Continuously Operating Reference Stations were analyzed to determine accurate displacements and P-waves. Validation with Indonesian geophysical agency seismic records indicated reliable detection of the horizontal component, with a time delay of less than 90 s, whereas the vertical component detection was inconsistent, owing to noise. Spectrogram analysis revealed P-wave energy in the pseudo-frequency range of 0.02–0.5 Hz and confirmed the method’s sensitivity to low-frequency signals. This approach illustrates the utility of GNSS data as a complement to seismic networks for the rapid characterization of earthquakes in complex tectonic regions. Improving the vertical component noise suppression might further help secure their utility in real-time early warning systems. Full article

The 2018 Sulawesi Earthquake and Tsunami serves as a backdrop for this work, which employs simple and straightforward remote sensing techniques to determine the extent of the destruction and indirectly evaluate the region’s vulnerability to such catastrophic events. Documenting damage from tsunamis is only meaningful shortly after the disaster has occurred because governmental agencies clean up debris and start the recovery process within a few hours after the destruction has occurred, deeming impact estimates unreliable. Sentinel-2 and Maxar WorldView-3 satellite images were used to calculate well-known environmental indices to delineate the tsunami-affected areas in Palu, Indonesia. The use of NDVI, NDSI, and NDWI indices has allowed for a quantifiable measure of the changes in vegetation, soil moisture, and water bodies, providing a clear demarcation of the tsunami’s impact on land cover. The final tsunami inundation map indicates that the areas most affected by the tsunami are found in the urban center, low-lying regions, and along the coast. This work charts the aftermath of one of Indonesia’s recent tsunamis but may also lay the groundwork for an easy, handy, and low-cost approach to quickly identify tsunami-affected zones. While previous studies have used high-resolution remote sensing methods such as LiDAR or SAR, our study emphasizes accessibility and simplicity, making it more feasible for resource-constrained regions or rapid disaster response. The scientific novelty lies in the integration of widely used environmental indices (dNDVI, dNDWI, and dNDSI) with threshold-based Decision Tree classification to delineate tsunami-affected areas. Unlike many studies that rely on advanced or proprietary tools, we demonstrate that comparable results can be achieved with cost-effective open-source data and straightforward methodologies. Additionally, we address the challenge of differentiating tsunami impacts from other phenomena (et, liquefaction) through index-based thresholds and propose a framework that is adaptable to other vulnerable coastal regions. Full article

Indonesia is situated on the Ring of Fire, which causes a lot of earthquakes. On the 28 September 2018, there was an earthquake in Palu, Sulawesi Island, Indonesia, which was one of the strongest shakings since 1980. Surprisingly, most traditional houses in Sulawesi survived. There has been some research on adapting traditional house structures to modern residential buildings. The limited availability of wood and complicated construction make adapting wood structures to current conditions challenging. The purpose of this study is to analyze space organization in ten traditional South Sulawesi house designs. A possible evacuation route can be found through the analysis as the first space for expeditiously escaping from an earthquake. In addition, modernizing the layout of a traditional South Sulawesi house and introducing it to local people was easy since they were familiar with the design. A deep analysis of spatial organization and its interrelations can help develop realistic designs, plans, and knowledge, thus improving the quality of residential projects. A descriptive qualitative method was used as a research method. Data were collected from field observations, brief interviews, and literature reviews. In order to analyz thee data, ORA-LITE was used to redraw the data and create the charts. It was found that different cultures have different evacuation spaces, in this case the Bugis tribe and the Toraja tribe. A corridor and kitchen were the most strategically located areas that could possibly be used for evacuation. Considering the differences in culture among tribes, designing evacuation spaces based on local culture was important. A recommendation based on this finding can also be made to the government of South Sulawesi in the design of residential houses. Full article

The air temperature changes in the Palu MW7.5 earthquake in Indonesia on 28 September 2018 were analyzed, based on the additive tectonic stress caused by celestial tidal-generating forces (ATSCTF) and air temperature data from the National Center for Environmental Prediction (NCEP). This paper explored the variation characteristics of three-dimensional stratified of air temperature caused by seismic activity and the coupling relationship between air temperature changes and the tidal force. The background information for air temperature calculation was obtained from the tidal force changes, and the air temperature increment method was used to study the temperature evolution process of different periods in the study area. The results found that the tidal force acting on the critical state earthquake faults may be an important external factor inducing earthquakes, and there was indeed a significant air temperature increase anomaly during the Palu MW7.5 earthquake. The paper also summarized the abnormal characteristics of air temperature caused by seismic activity: the air temperature closer to the land’s surface has greater anomaly amplitude and a wider anomaly area than that of the upper air. Full article

The Mw 7.5 Palu earthquake that occurred on 28 September 2018 (UTC 10:02) on Sulawesi Island, Indonesia, triggered approximately 15,600 landslides, causing about 4000 fatalities and widespread destruction. The primary objective of this study is to perform landslide susceptibility mapping (LSM) associated with this event and assess the performance of the most widely used machine learning algorithms of logistic regression (LR) and random forest (RF). Eight controlling factors were considered, including elevation, hillslope gradient, aspect, relief, distance to rivers, peak ground velocity (PGV), peak ground acceleration (PGA), and lithology. To evaluate model uncertainty, training samples were randomly selected and used to establish the models 20 times, resulting in 20 susceptibility maps for different models. The quality of the landslide susceptibility maps was evaluated using several metrics, including the mean landslide susceptibility index (LSI), modelling uncertainty, and predictive accuracy. The results demonstrate that both models effectively capture the actual distribution of landslides, with areas exhibiting high LSI predominantly concentrated on both sides of the seismogenic fault. The RF model exhibits less sensitivity to changes in training samples, whereas the LR model displays significant variation in LSI with sample changes. Overall, both models demonstrate satisfactory performance; however, the RF model exhibits superior predictive capability compared to the LR model. Full article

This paper presents the results of the subsurface investigation and liquefaction assessment of the Petobo flowslide, induced by soil liquefaction during the Mw 7.5 Palu–Donggala earthquake of Indonesia on 28 September 2018. The investigations, including drilling, standard penetration tests, electrical resistivity imaging survey, dynamic probing, groundwater table monitoring, etc., were conducted along the main road that passes through the middle of the flowslide area. Liquefaction assessments and flowslide simulations were carried out with three assumed scenarios. Scenario 1 describes the condition if the flowslide were to be retriggered at the cease of sliding due to the same earthquake striking the site. Scenarios 2 and 3 attempt to examine the influence of locally raised groundwater levels due to the infiltration of the Gumbasa irrigation system and widespread paddy fields of the site as a result of soil liquefaction and the flowslide. Subsurface investigations revealed that, within a 30-m depth of the ground, the sliding area generally consists of sandy deposits of SM/SP/SW, except for the toe portion where thick layers of silt (ML) and clay (CL) were found. The results of field testing and liquefaction assessment identify potentially weak and liquefiable zones which enable the construction of a speculated slip surface for the flowslide. Both liquefaction assessment and flowslide simulations verify that soil liquefaction would be triggered during the earthquake as a result of locally raised groundwater tables, and that a gentle slope (≈3°) that provides static shears would lead to long-distance sliding after shaking. Should the locally raised groundwater tables not exist, the results indicate no soil liquefaction and no flowslide. Full article

The distribution of tsunami runup heights along the coast is studied both theoretically and experimentally using observation data of historical tsunami from 1992 to 2018. The physical mechanisms leading to the lognormal distribution of tsunami runup heights along the coast are discussed, and its statistical moments are calculated. It is shown that the lognormal distribution describes well the measurements of tsunami characteristics over the past 30 years. Special attention is paid to the multi-source 2018 Palu–Sulawesi tsunami, which was generated by an earthquake with magnitude 7.5 and numerous subsequent landslides. It is shown that even in this special case the lognormal distribution is a rather good approximation. Full article

The study of ionospheric disturbances associated with the two large strike-slip earthquakes in Indonesia was investigated, which are West Sumatra on 2 March 2016 (Mw = 7.8), and Palu on 28 September 2018 (Mw = 7.5). The anomalies were observed by measuring co-seismic ionospheric disturbances (CIDs) using the Global Navigation Satellite System (GNSS). The results show positive and negative CIDs polarization changes for the 2016 West Sumatra earthquake, depending on the position of the satellite line-of-sight, while the 2018 Palu earthquake shows negative changes only due to differences in co-seismic vertical crustal displacement. The 2016 West Sumatra earthquake caused uplift and subsidence, while the 2018 Palu earthquake was dominated by subsidence. TEC anomalies occurred about 10 to 15 min after the two earthquakes with amplitude of 2.9 TECU and 0.4 TECU, respectively. The TEC anomaly amplitude was also affected by the magnitude of the earthquake moment. The disturbance signal propagated with a velocity of ~1–1.72 km s⁻¹ for the 2016 West Sumatra earthquake and ~0.97–1.08 km s⁻¹ for the 2018 Palu mainshock earthquake, which are consistent with acoustic waves. The wave also caused an oscillation signal of ∼4 mHz, and their azimuthal asymmetry of propagation confirmed the phenomena in the Southern Hemisphere. The CID signal could be identified at a distance of around 400–1500 km from the epicenter in the southwestern direction. Full article

Our understanding of pull-apart basins and their fault systems has been enhanced by analog experiments and simulations. However, there has been scarce interest to compare the faults that bound pull-apart basins with surface ruptures during earthquakes. In this study, we investigated the effects of a 2018 earthquake (Mw 7.5) on a pull-apart basin in the Palu–Koro fault system, Sulawesi Island, Indonesia, using geomorphic observations on digital elevation models and optical correlation with pre- and post-earthquake satellite images. A comparison of active fault traces determined by geomorphology with the locations of surface ruptures from the 2018 earthquake shows that some of the boundary faults of the basin are inactive and that active faulting has shifted to basin-shortcut faults and relay ramps. We also report evidence of lateral spreading, in which alluvial fan materials moved around the end of the alluvial fan. These phenomena may provide insights for anticipating the location of future surface ruptures in pull-apart basins. Full article

Building-damage mapping using remote sensing images plays a critical role in providing quick and accurate information for the first responders after major earthquakes. In recent years, there has been an increasing interest in generating post-earthquake building-damage maps automatically using different artificial intelligence (AI)-based frameworks. These frameworks in this domain are promising, yet not reliable for several reasons, including but not limited to the site-specific design of the methods, the lack of transparency in the AI-model, the lack of quality in the labelled image, and the use of irrelevant descriptor features in building the AI-model. Using explainable AI (XAI) can lead us to gain insight into identifying these limitations and therefore, to modify the training dataset and the model accordingly. This paper proposes the use of SHAP (Shapley additive explanation) to interpret the outputs of a multilayer perceptron (MLP)—a machine learning model—and analyse the impact of each feature descriptor included in the model for building-damage assessment to examine the reliability of the model. In this study, a post-event satellite image from the 2018 Palu earthquake was used. The results show that MLP can classify the collapsed and non-collapsed buildings with an overall accuracy of 84% after removing the redundant features. Further, spectral features are found to be more important than texture features in distinguishing the collapsed and non-collapsed buildings. Finally, we argue that constructing an explainable model would help to understand the model’s decision to classify the buildings as collapsed and non-collapsed and open avenues to build a transferable AI model. Full article

We obtained high-resolution (10 m) horizontal displacement fields from pre- and post-seismic Sentinel-2 optical images of the 2018 Mw7.5 Palu earthquake using subpixel image correlation. From these, we calculated the curl, divergence, and shear strain fields from the north-south (NS) and east-west (EW) displacement fields. Our results show that the surface rupture produced by the event was distributed within the Sulawesi neck (0.0974–0.6632°S) and Palu basin (0.8835–1.4206°S), and had a variable strike of 313.0–355.2° and strike slip of 2.00–6.62 m. The NS and EW displacement fields within the Palu basin included fine-scale displacements in both the near- and far-fault, the deformation patterns included a small restraining bend (localized shortening), a distributed rupture zone, and a major releasing bend (net extension) from the curl, divergence, and shear strain. Surface rupture was dominated by left-lateral strike-slip from initiation to termination, with a localized normal slip component peaking at ~3.75 m. The characteristics and geometric variation of the ruptured fault controlled both the formation of these surface deformation patterns and sustained supershear rupture. Full article

Exploration of posttraumatic growth (PTG) experiences in adolescent survivors of earthquakes, tsunamis, or liquefaction are needed by nurses to maximize the potential for recovery and growth of adolescents from trauma after natural disasters. The study used a qualitative method with a descriptive phenomenology approach. Data were collected through in-depth interviews with 16 adolescent survivors and were analyzed using the Colaizzi method. The results of this study have two main themes: trauma becoming the basis for realizing the meaning of life and escaping from disaster as a second chance to live better. PTG is a positive change that needs to be pursued. Escaping from disaster and realizing the meaning of life are the key points to get success in pursuing PTG to live a better life. In addition, support from mental health nurses through cognitive therapy (CT) and acceptance commitment therapy (ACT) are needed to increase the PTG. Full article

Disasters have been striking human-beings from the beginning of history and their management is a global concern of the international community. Minimizing the impact and consequences of these disasters, both natural and human-made, involves many decision and logistic processes that should be optimized. A crucial logistic problem is the evacuation of the affected population, and the focus of this paper is the planning of supported evacuation of vulnerable people to safe places when necessary. A lexicographic goal programming model for supported evacuation is proposed, whose main novelties are the classification of potential evacuees according to their health condition, so that they can be treated accordingly; the introduction of dynamism regarding the arrival of potential evacuees to the pickup points, according to their own susceptibility about the disaster and the joint consideration of objectives such us number of evacuated people, operation time and cost, among which no trade-off is possible. The performance of the proposed model is evaluated through a realistic case study regarding the earthquake and tsunami that hit Palu (Indonesia) in September 2018. Full article

We use both Synthetic Aperture Radar (SAR) and Optical data to constrain the co-seismic ground deformation produced by the 2018 M_w 7.5 Sulawesi earthquake. We exploit data processing techniques mainly based on pixel cross-correlation approach, applied to Synthetic Aperture Radar (SAR) and optical images to estimate the North–South (NS) displacement component. This component is the most significant because of the NNW–SSE geometry of the fault responsible for the seismic event, i.e., the Palu-Koro fault, characterized by a strike-slip faulting mechanism. Our results show a good agreement between the different data allowing to clearly identify the surface rupture due to the fault slip. Moreover, we use SAR and optical intensity images to investigate several secondary phenomena generated by the seismic event such as tsunami, landslides, and coastal retreat. Finally, we discuss differences between SAR and optical outcomes showing strengths and disadvantages of each one according to the investigated phenomenon. Full article