Search Results (19)

Historically known for its tin mining industry, Phuket Island has undergone significant transformation into a global tourism hub. This study aims at analyzing the evolutionary dynamics of Phuket Island from the years 1987 to 2024. We integrate Landsat satellite images and sophisticated analytical methods to assess the effects of tourism and economic policies on changes in land use and land cover using Google Earth Engine (GEE) for cloud-based data processing and Random Forest (RF) models for classification, and the Urban Expansion Intensity Index (UEII) and Shannon Entropy metrics for measuring the intensity of urban expansion and diversity, respectively. The results show that there has been a dynamic change in the patterns of land use which was brought about by the economic and environmental forces. Some of the major events that have had a great effect on Phuket’s landscape include the 1997 Asian Financial Crisis, the 2004 Indian Ocean Tsunami, and the COVID-19 pandemic; this highlights how the island is fragile and can be affected easily by events happening around the world. This work reveals a dramatic reduction in forest and mangrove cover, which calls for increased conservation measures to prevent the loss of biodiversity and to preserve the natural balance. Full article

On 28 March 2005, a major M_w 8.6 earthquake occurred near Nias and Simeulueislands, in the vicinity of northwestern Sumatra (Indonesia). The earthquake generated a significant tsunami. Although it was not as destructive as the 2004 Sumatra tsunami, the 2005 event was of sufficient strength to be recorded by tide gauges throughout the entire Indian Ocean. We selected 12 records for analysis, most from open-ocean islands but also some from continental stations. The maximum wave heights were measured at Salalah (Oman) (87 cm), Colombo (Sri Lanka), Pointe La Rue (Seychelles) and Rodrigues Island (53–54 cm). The dominant wave periods, estimated from frequency–time (f-t) diagrams, were 60–66 min, 40–48 min, and 20 min, which we assume are associated with the 2005 tsunami source. From the same stations, we calculated the mean ratio of the 2004 to 2005 tsunami heights as 5.11 ± 0.60, with the maximum and minimum heights to the west and south of the source region as 9.0 and 2.49, respectively. We also used these data to estimate the mean energy index, $E_0$ = 65 cm², for the 2005 tsunami, which was 16 times smaller than for the 2004 event. The USGS seismic solution was used to construct a numerical model of the 2005 tsunami and to simulate the tsunami waveforms for all 12 tide gauge stations. The results of the numerical computations were in general agreement with the observations and enabled us to map the spatial wave field of the event. To estimate the influence of location and orientation of the source area on the propagating tsunami waves, we undertook a set of additional numerical experiments and found that this influence is substantial and that these factors explain some of the differences between the physical properties of the 2004 and 2005 events. Full article

Tsunamis are a substantial natural threat in Thailand, as evidenced by the 2004 Indian Ocean tsunami. Effective evacuation is vital to reduce casualties and property damage. However, despite improved warning systems, high death tolls still occur, indicating complex evacuation behavior influenced by various factors. This study examines these factors among diverse groups in Phuket and Phang Nga, Thailand. A survey of 1000 locals, non-local workers, and travelers assesses threat and coping appraisals, past tsunami experiences, gender, age, and tsunami evacuation intention and action selection. Partial Least Squares Structural Equation Modeling (PLS-SEM) was used to analyze the data based on the hypotheses related to the Protection Motivation Theory (PMT). The results of the analyses show that threat and coping appraisals significantly predict tsunami evacuation intention, and gender influences threat perception related to evacuation. Variations among respondent types emphasize the need for tailored disaster preparedness and response strategies. This study offers crucial insights for policymakers, emergency responders, and disaster management stakeholders, underlining the significance of further research into the intricate interplay of individual and contextual factors shaping tsunami evacuation behavior. Full article

The assessment of post-disaster recovery is often hindered by limited metric and longitudinal data, in addition to the dynamic and long-term processes. Therefore, this study aimed to investigate the early stages after the 2004 Indian Ocean tsunami in Aceh, Indonesia, using the Disaster Recovery Index (DRI). The two initial waves of Study of Tsunami and Aftermath Recovery (STAR) data were used to track the recovery process from 5 to 19 months after the tsunami. The results showed various recovery patterns in three affected areas and five sectors. Furthermore, recovery rates in the medium and heavily damaged areas increased by 2.05 and 7.45 percentage points, respectively, with a 0.33 percentage point decrease in the lightly damaged areas. The social and livelihood sectors showed rapid progress, supported by the establishment of temporary health and education facilities, including Cash-for-Work programs. Meanwhile, other sectors experienced slower recovery due to their complexity. The application of the DRI successfully showed the relative positions across affected areas and sectors over time in a simple way. This confirmed the variety of recoveries in subgroups in the community and suggested the importance of regularly measuring progress using standard metrics to observe long-term conditions. Full article

The 2004 Indian Ocean earthquake and tsunami significantly impacted the coastal shoreline of the Andaman and Nicobar Islands, causing widespread destruction of infrastructure and ecological damage. This study aims to analyze the short- and long-term shoreline changes in South Andaman, focusing on 2004–2005 (pre- and post-tsunami) and 1990–2023 (to assess periodic changes). Using remote sensing techniques and geospatial tools such as the Digital Shoreline Analysis System (DSAS), shoreline change rates were calculated in four zones, revealing the extent of the tsunami’s impact. During the pre- and post-tsunami periods, the maximum coastal erosion rate was −410.55 m/year, while the maximum accretion was 359.07 m/year in zone A, the island’s east side. For the 1990–2023 period, the most significant coastal shoreline erosion rate was also recorded in zone A, which was recorded at −2.3 m/year. After analyzing the result, it can be seen that the tsunami severely affected the island’s east side. To validate the coastal shoreline measurements, the root mean square error (RMSE) of Landsat-7 and Google Earth was 18.53 m, enabling comparisons of the accuracy of different models on the same dataset. The results demonstrate the extensive impact of the 2004 Indian Ocean Tsunami on South Andaman’s coastal shoreline and the value of analyzing shoreline changes to understand the short- and long-term consequences of such events on coastal ecosystems. This information can inform conservation efforts, management strategies, and disaster response plans to mitigate future damage and allocate resources more efficiently. By better understanding the impact of tsunamis on coastal shorelines, emergency responders, government agencies, and conservationists can develop more effective strategies to protect these fragile ecosystems and the communities that rely on them. Full article

This study is about the electrification of the remote islands in the Indian Ocean that were severely affected by the tsunami in the 2004 earth earthquake. To supply electricity to the islands, two diesel generators with capacities of 110 kW and 60 kW were installed in 2019. The feasibility of using renewable energy to supplement or replace the units in these two generators is investigated in this work. In 2019, two diesel generators with capacities of 110 kW and 60 kW were installed in the islands to supply electricity. This work analyses whether the viability of using renewable energy can be used to supplement or replace these two generators. Among the renewable energy options proposed here are a 100 kW wind turbine, solar PV, a converter, and batteries. As a result, the study’s goal is to perform a techno-economic analysis and optimise the proposed hybrid diesel and renewable energy system for a remote island in the Indian Ocean. The Hybrid Optimisation Model for Electric Renewable (HOMER) Pro software was used for all simulations and optimisation for this analysis. The calculation is based on the current diesel price of USD 0.90 per litre (without subsidy). The study found that renewable alone can contribute to 29.2% of renewable energy fractions based on the most optimised systems. The Net Present Cost (NPC) decreased from USD 1.65 million to USD 1.39 million, and the levelised Cost of Energy (CoE) decreased from 0.292 USD/kWh to 0.246 USD/kWh, respectively. The optimised system’s Internal Rate of Return (IRR) is 14% and Return on Investment (ROI) 10%, with a simple payback period of 6.7 years. This study shows that it would be technically feasible to introduce renewable energy on a remote island in Indonesia, where numerous islands have no access to electricity. Full article

The tsunami is one of the deadliest natural disasters, responsible for more than 260,000 deaths and billions in economic losses over the last two decades. The footage of the devastating power of the 2004 Indian Ocean tsunami perhaps remains vivid in the memory of most survivors, and Malaysia was one of the countries affected by the unprecedented 2004 tsunami. It was the first time the Malaysian government had managed such a great disaster. This review, therefore, gathers the relevant literature pertaining to the efforts undertaken following the event of the 2004 tsunami from Malaysia’s perspective. A compilation of post-event observations regarding tsunami characteristics is first presented in the form of maps, followed by building damage, including damage modes of wall failure, total collapse, debris impact and tilting of structures. In addition, hazard assessments and projections regarding a hypothetical future tsunami towards vulnerable hazard zones in Malaysia are reviewed. It is observed that future tsunami risks may originate from the Indian/Burma Plate, Andaman Island, Sunda Trench, Manila Trench, Sulu Trench, Negro Trench, Sulawesi Trench, Cotabato Trench and Brunei slide. A rundown of post-2004 measures and tsunami research undertaken in the country is also included in this review, serving as a reference for disaster management globally. Overall, the outcomes of this review are important for understanding tsunami vulnerability and the resilience of coastal infrastructures, which will be crucial for continued progress in the future. Full article

Little is known about whether the provision of aid in the aftermath of a large-scale natural disaster affects psychological well-being. We investigate the effects of housing assistance, a key element of the reconstruction program implemented after the 2004 Indian Ocean tsunami. Population-representative individual-level longitudinal data collected in Aceh, Indonesia, during the decade after the tsunami as part of the Study of the Tsunami Aftermath and Recovery (STAR) are used. Housing aid was targeted to people whose homes were destroyed and, to a lesser extent, damaged by the tsunami and to those who lived, at the time of the tsunami, in communities that sustained the greatest damage. The effects of receipt of aid on post-traumatic stress reactivity (PTSR) are examined using panel data models that take into account observed and unobserved individual-specific fixed characteristics that affect both PTSR and aid receipt, drawing comparisons in each survey wave between individuals who had been living in the same kecamatan when the tsunami hit. Those who received aid have better psychological health; the effects increase with time since aid receipt and are the greatest at two years or longer after the receipt. The effects are concentrated among those whose homes were destroyed in the tsunami. Full article

The aftermath of the Indian Ocean tsunami on 26 December 2004 triggered by the off Sumatra earthquake (magnitude “M” = 9.1), and the Great East Japan earthquake of 11 March 2011 off the Pacific coast of Tohoku (M = 9.0), evidence the secondary damage from driftage collision due to large tsunami waves. To prevent this type of damage, the establishment of methods for predicting driftage movement and calculating the impact force by driftage is necessary. Several numerical models have been developed to predict the driftage movement of objects. Every year, these improve in accuracy and usability. In contrast, there are many calculation formulae for calculating the impact force. However, since there are considerable differences between values calculated using these formulae, the reliability of each formula is unknown. Therefore, in this research, one team of the committee on tsunami research of the Japan Society of Civil Engineers summarizes the main calculation formulae of impact forces that have been proposed until 2019. In addition, for each type of driftage (driftwood, containers, cars, ships), we compare calculation values of these formulae with measured data of large-scale experiments. Finally, we check the range of calculation values for each formula up to 15 m/s in collision velocity and clarify then the following facts: (1) In the case of driftwood, the formulae of Matsutomi, Federal Emergency Management Agency (FEMA) and National Oceanic and Atmospheric Administration (NOAA), and American Society of Civil Engineers (ASCE) are most reliable; (2) In the case of containers, the formulae of Matsutomi, Arikawa et al., FEMA and NOAA, Ikeno et al., and ASCE are most reliable; (3) In the case of cars, the formulae of FEMA and NOAA, and ASCE are most reliable; (4) In the case of ships, the formulae of Mizutani, FEMA and NOAA, and ASCE are most reliable. Full article

Tsunamis are among the deadliest threats to coastal areas as reminded by the recent tragic events in the Indian Ocean in 2004 and in Japan in 2011. A large number of tropical islands are indeed exposed due to their proximity to potential tsunami sources in tectonic subduction zones. For these territories, assessing tsunamis’ impact is of major concern for early warning systems and management plans. The effectiveness of inundation predictions relies, among other things, on processes engaged at the scale of the local bathymetry and topography. As part of the project C3AF that aimed to study the consequences of climate change on the French West Indies, we used the numerical model SCHISM to simulate the propagation of several potential tsunamis as well as their impacts on the Guadeloupe islands (French West Indies). Working from the findings of the most recent studies, we used the simulations of four scenarios of collapse of the Cumbre Vieja volcano in La Palma, Canary islands. We then used FUNWAVE-TVD to simulate trans-Atlantic wave propagation until they reached the Guadeloupe archipelago where we used SCHISM to assess their final impact. Inundation is quantified for the whole archipelago and detailed for the most exposed areas. Finally, in a climate change perspective, inundation is compared for different sea levels and degrees of vegetation cover deterioration using modified friction coefficients. We then discuss the results showing that climate change-related factors would amplify the impact more in the case of smaller inundation along with model limitations and assumptions. Full article

Community resilience is increasingly required to adapt to the effects of the frequency and severity of the ever-increasing number of coastal hazards. This paper uses the case study of the city of Banda Aceh, Indonesia, which was devastated by the 2004 Indian Ocean Tsunami, with the aim of investigating the city’s level of resilience towards coastal hazards. This paper aims to: (i) assess the preparedness of coastal communities; (ii) evaluate the level of resilience of the city to coastal hazards; and (iii) formulate strategic steps in an effort to mitigate coastal hazards in Banda Aceh. The evaluation was conducted using mixed methods (both quantitative and qualitative) through data triangulation. Data collection involved 311 household surveys, two focus group discussions with 30 participants, and interviews with seven representatives from government and non-government organisations. Regarding the survey, the preparedness level of Banda Aceh’s residents is categorised as “low“. The results of overall city resilience assessments are also classified as “low”. This finding indicates that more planned, systematic, and sustainable efforts are needed. Hence, this study also recommends strategies to enhance resilience in dealing with coastal hazards. Full article

In the case of huge tsunamis, such as the 2004 Great Indian Ocean Tsunami and 2011 Great East Japan Tsunami, the damage caused by ground scour is serious. Therefore, it is important to improve prediction models for the topographical change of huge tsunamis. For general models that predict topographical change, the flow velocity distribution of a flood region is calculated by a numerical model based on a nonlinear long wave theory, and the distribution of bed-load rates is calculated using this velocity distribution and an equation for evaluating bed-load rates. This bed-load rate equation usually has a coefficient that can be decided using verification simulations. For the purpose, Ribberink’s formula has high reproducibility within an oscillating flow and was chosen by the authors. Ribberink’s formula needs a bed-load transport coefficient that requires sufficient verification simulations, as it consumes plenty of time and money to decide its value. Therefore, the authors generated diagrams that can define the suitable bed-load coefficient simply using the data acquired from hydraulic experiments on a movable bed. Subsequently, for the verification purpose of the model, the authors performed reproduced simulations of topography changes caused by the 2011 Great East Japan Tsunami at some coasts in Northern Japan using suitable coefficients acquired from the generated diagrams. The results of the simulations were in an acceptable range. The authors presented the preliminary generated diagrams of the same methodology but with insubstantial experimental data at the time at the International Society of Offshore and Polar Engineers (ISOPE), (2018 and 2019). However, in this paper, an adequate amount of data was added to the developed diagrams based on many hydraulic experiments to further raise their reliability and their application extent. Furthermore, by reproducing the tsunami simulation on the Sendai Natori coast of Japan, the authors determined that the impact of total bed-load transport was much bigger than that of suspension loads. Besides, the simulation outputs revealed that the mitigation effect of the cemented sand and gravel (CSG) banks and artificial refuge hills reduced tsunami damage on Japan’s Hamamatsu coast. Since a lot of buildings and structures in the inundation area can be destroyed by tsunamis, building destruction design was presented in this paper through an economy and simplified state. Using the proposed tsunami simulation model, we acquired the inundation depth at any specific time and location within the inundated area. Because the inundation breadth due to a huge tsunami can extend kilometers toward the inland area, the evaluation of building destruction is an important measure to consider. Therefore, the authors in this paper presented useful threshold diagrams to evaluate building destruction with an easy and cost-efficient state. The threshold diagrams of “width of a pillar” for buildings or “width of concrete block walls” not breaking to each inundation height were developed using the data of damages due to the 2011 Great East Japan Tsunami. Full article

The 2004 Indian Ocean tsunami caused massive morphological changes around the coast of Sumatra, Indonesia. This research investigates the coastal morphological changes in the Banda Aceh area via coupling a hydrodynamic model with a sediment transport module. The Cornell Multigrid Coupled Tsunami Model (COMCOT) was coupled with the XBeach Model to simultaneously simulate sediment transport and the hydrodynamic process during the tsunami. The coupled model is known as COMCOT-SED. Field bathymetric data measured in 2006 were used to validate the coupled model. This study reveals that the tsunami’s impact was more severe on the eastern part of the coast, where it hit directly. Meanwhile, the western part of the coast suffered a lower impact because of the sheltering effects from a series of small islands and a headland to the north. This study has shown that the model results from COMCOT-SED are consistent with field data and show where the tsunami waves caused offshore erosion. Full article

Marine geohazard research has developed during recent decades, as human activities intensified towards deeper waters. Some recent disastrous events (e.g., the 2004 Indian Ocean and 2011 Japan tsunamis) highlighted geohazards socioeconomic impacts. Marine geohazards encompass an extensive list of features, processes, and events related to Marine Geology. In the scientific literature there are few systematic reviews concerning all of them. Using the search string ‘geohazard*’, this bibliometric-based review explored the scientific databases Web of Science and Scopus to analyze the evolution of peer-reviewed scientific publications and discuss trends and future challenges. The results revealed qualitative and quantitative aspects of 183 publications and indicated 12 categories of hazards, the categories more studied and the scientific advances. Interdisciplinary surveys focusing on the mapping and dating of past events, and the determination of triggers, frequencies, and current perspectives of occurrence (risk) are still scarce. Throughout the upcoming decade, the expansion and improvement of seafloor observatories’ networks, early warning systems, and mitigation plans are the main challenges. Hazardous marine geological events may occur at any time and the scientific community, marine industry, and governmental agencies must cooperate to better understand and monitor the processes involved in order to mitigate the resulting unpredictable damages. Full article