Tsunami Exposure Research Articles

Impact of the 2004 Tsunami on Self-Reported Physical Health in Thailand for the Subsequent 2 Years

We examined self-reported physical health during the first 2 years following the 2004 tsunami in Thailand. We assessed physical health with the revised Short Form Health Survey. We evaluated 6 types of tsunami exposure: personal injury, personal loss of home, personal loss of business, loss of family member, family member's injury, and family's loss of business. We examined the relationship between tsunami exposure and physical health with multivariate linear regression. One year post-tsunami, we interviewed 1931 participants (97.2% response rate), and followed up with 1855 participants 2 years after the tsunami (96.1% follow-up rate). Participants with personal injury or loss of business reported poorer physical health than those unaffected (P < .001), and greater health impacts were found for women and older individuals. Exposure to the tsunami disaster adversely affected physical health, and its impact may last for longer than 1 year, which is the typical time when most public and private relief programs withdraw.

Impact of exposure to conflict, tsunami and mental disorders on school absenteeism: findings from a national sample of Sri Lankan children aged 12–17 years

BackgroundArmed conflicts and natural disasters are common. Millions of people, including children are killed, injured, disabled and displaced as a result. The effects of conflict and natural disaster on mental health, especially of children are well established but effects on education have received less attention. This study investigated associations between conflict and/or tsunami exposure in Sri Lanka and their associations with absenteeism in a national sample of school children.MethodsA cross-sectional survey was conducted in 2006–7 among 1,505 randomly selected school children aged 12–17 years attending government schools in 17 districts. The hypotheses were that absenteeism would be more common in children previously affected by conflict or the 2004 tsunami and that at least part of this effect would be accounted for by mental disorders. Survey information included socio-demographic, conflict and tsunami exposure, mental health status (Strengths and Difficulties Questionnaire) and information on absenteeism (defined as 20% or greater non-attendance over one year).ResultsThe total sample of consisted of 1,505 students aged 12–17 years with a mean age of 13.7 years. 120 children reported at least one conflict exposure and 65 reported at least one tsunami exposure while only 15 reported exposure to both conflict and tsunami. Prevalence of emotional disorder caseness was 2.7%, conduct disorder caseness 5.8%, hyperactivity disorder caseness 0.6%, and 8.5% were identified as having any psychiatric disorder. Absenteeism was present in 26.8%. Overall, previous exposure to tsunami (OR 2.29 95% CI 1.36-3.84) was significantly associated with absenteeism whereas exposure to conflict was not (OR 1.32 95% CI 0.88-1.97), although some specific conflict-related exposures were significant risk factors. Mental disorder was strongly associated with absenteeism but did not account for its association with tsunami or conflict exposure.ConclusionsExposure to traumatic events may have a detrimental effect on subsequent school attendance. This may give rise to perpetuating socioeconomic inequality and needs further research to inform policy and intervention.

Development of an online tool for tsunami inundation simulation and tsunami loss estimation

The devastating impacts of the 2004 Indian Ocean tsunami highlighted the need for an effective end-to-end tsunami early warning system in the region that connects the scientific components of warning with preparedness of institutions and communities to respond to an emergency. Essential to preparedness planning is knowledge of tsunami risks. In this study, development of an online tool named “INSPIRE” for tsunami inundation simulation and tsunami loss estimation is presented. The tool is designed to accommodate various accuracy levels of tsunami exposure data which will support the users to undertake preliminary tsunami risk assessment from the existing data with progressive improvement with the use of more detailed and accurate datasets. Sampling survey technique is introduced to improve the local vulnerability data with lower cost and manpower. The performance of the proposed methodology and the INSPIRE tool were tested against the dataset in Kamala and Patong municipalities, Phuket province, Thailand. The estimated building type ratios from the sampling survey show the satisfactory agreement with the actual building data at the test sites. Sub-area classification by land use can improve the accuracy of the building type ratio estimation. For the resulting loss estimation, the exposure data generated from detailed field survey can provide the agreeable results when comparing to the actual building damage recorded for the Indian Ocean tsunami event in 2004. However, lower accuracy exposure data derived from sampling survey and remote sensing can still provide a comparative overview of estimated loss.

PROBABILISTIC TSUNAMI HAZARD ANALYSIS AND RISK TO COASTAL POPULATIONS IN THAILAND

The study of tsunami hazards in Thailand has been an ongoing topic of research. However, the hazards from tsunami sources based on probabilistic study and population risk are still unclear. In this study, potential tsunami sources along rupture zones were selected. A series of far-field tsunami simulations were performed with scaled fault parameters based on fault lengths from 100–600 km. The results show that within a few centuries, the maximum tsunami height could be 2–5 m at the west coast and less than 2 m at the east coast. The potential tsunami exposure (PTE) of populations in an estimated inundation zone was calculated using global population data in relation to tsunami height. The results show that much attention should be paid to fault ruptures longer than 300 km (≈ 8.5 moment magnitude, Mw) that originate from 4°–6° N and 14°–17° N for the Sumatra subduction zone and the Manila trench, respectively. A quarter of a million people are at risk of exposure to a maximum 9 m tsunami height after 100 min of the arrival of the first wave at the Andaman coast. One million people near the Gulf of Thailand are at risk of a tsunami height less than 3 m after 9 hr.

Tsunami hazard in the Caribbean: Regional exposure derived from credible worst case scenarios

The present study documents a high tsunami hazard in the Caribbean region, with several thousands of lives lost in tsunamis and associated earthquakes since the XIXth century. Since then, the coastal population of the Caribbean and the Central West Atlantic region has grown significantly and is still growing. Understanding this hazard is therefore essential for the development of efficient mitigation measures. To this end, we report a regional tsunami exposure assessment based on potential and credible seismic and non-seismic tsunamigenic sources. Regional tsunami databases have been compiled and reviewed, and on this basis five main scenarios have been selected to estimate the exposure. The scenarios comprise two Mw8 earthquake tsunamis (north of Hispaniola and east of Lesser Antilles), two subaerial/submarine volcano flank collapse tsunamis (Montserrat and Saint Lucia), and one tsunami resulting from a landslide on the flanks of the Kick'em Jenny submarine volcano (north of Grenada). Offshore tsunami water surface elevations as well as maximum water level distributions along the shore lines are computed and discussed for each of the scenarios. The number of exposed people has been estimated in each case, together with a summary of the tsunami exposure for the earthquake and the landslide tsunami scenarios. For the earthquake scenarios, the highest tsunami exposure relative to the population is found for Guadeloupe (6.5%) and Antigua (7.5%), while Saint Lucia (4.5%) and Antigua (5%) have been found to have the highest tsunami exposure relative to the population for the landslide scenarios. Such high exposure levels clearly warrant more attention on dedicated mitigation measures in the Caribbean region.

The living environment and children's fears following the Indonesian tsunami.

The tsunami that struck South-east Asia on 26 December 2004 left more than 500,000 people in Aceh, Indonesia, homeless and displaced to temporary barracks and other communities. This study examines the associations between prolonged habitation in barracks and the nature of fears reported by school-age children and adolescents. In mid-2007, 30 months after the tsunami, the authors interviewed 155 child and parent dyads. Logistic regression analysis was used to compare the fears reported by children and adolescents living in barracks with those reported by their peers who were living in villages. After adjusting for demographic factors and tsunami exposure, the data reveals that children and adolescents living in barracks were three times more likely than those living in villages to report tsunami-related fears. The study demonstrates that continued residence in barracks 30 months after the tsunami is associated with higher rates of reporting tsunami-related fears, suggesting that barracks habitation has had a significant impact on the psychological experience of children and adolescents since the tsunami.

Change in the health of tsunami-exposed mothers three years after the natural disaster

Women's experiences with secondary stressors resulting from natural disasters, such as increased economic insecurity, expanded caregiving responsibilities and disrupted family life, may contribute to women's mental and physical health problems. The present study investigates change and stability in post-tsunami depressive symptoms and perceived physical health of tsunami-exposed mothers over three and a half years. Using data from 160 tsunami-affected mothers, the present study uses structural equation modelling to investigate (1) change, stability, cross-lagged reciprocal influences of mental and physical health and (2) the meditation effect of negative life events on the relationship between tsunami exposure and post-tsunami depressive symptoms and perceived physical health of tsunami-exposed mothers from 2005 to 2008. Tsunami exposure contributed to depressive symptoms among mothers independently of pre-tsunami family adversities. Average depressive symptoms showed a decline whereas poor physical health showed an increase over this period. The results also revealed an interrelated health process between depression and physical health over time. Continuity of health problems were mediated by secondary stressors that also exerted an additive effect on later health problems. Post-disaster intervention and recovery programmes should focus not only on mothers' exposure to natural disasters, but also their pre- and post-natural disaster adversities. They should reach disaster-exposed mothers directly and have an integrated health approach to disrupt continuities of health problems.

School-Based Intervention for the Treatment of Tsunami-Related Distress in Children: A Quasi-Randomized Controlled Trial

Background: On December 26, 2004, a tsunami hit the southern coast of Sri Lanka, leaving thousands dead and injured. Previous research has found significant mental health problems among children exposed to major disasters. School-based universal interventions have shown promise in alleviating distress and posttraumatic symptomatology in children and adolescents. This study evaluated the efficacy of a school-based intervention in reducing stress-related symptomatology among Sri Lankan children exposed to the tsunami. Methods: In a quasi-randomized controlled trial 166 elementary school students (ages 9–15) with significant levels of tsunami exposure and previous traumatic background were randomly assigned to a 12-session structured program ‘ERASE Stress Sri Lanka’ (ES-SL) or to a waiting list (WL) religious class control group. Students were assessed 1 week prior and 3 months after the intervention on measures of posttraumatic symptomatology [including posttraumatic stress disorder (PTSD) and severity of posttraumatic symptomatology], depression, functional problems, somatic problems and hope. Results: This study shows a significant reduction on all outcome variables. PTSD severity, functional problems, somatic complaints, depression and hope scores were all significantly improved in the ES-SL group compared to the WL group. No new cases of PTSD were observed in the experimental group. Conclusion: This study adds to the growing body of evidence suggesting the efficacy of school-based universal approaches in helping children in regions touched by war, terror and disaster and suggests the need to adopt a two-stage approach toward dealing with trauma-exposed students, namely, starting with a universal intervention followed by targeted specialized interventions for those still suffering from posttraumatic distress.

P03-255 Quality of life among the navies at six months after the tsunami in phang-NGA naval base, phang-NGA province, Thailand

Objective:This study aimed to identify the health-related quality of life (HRQOL) among the navies or their spouses at 6 months after the tsunami disaster, to compare HRQOL with the 2006 Thailand normative data for Short Form - 36 (Bangkok)4.Method:A structured questionnaire modified from the 36-item Medical Outcome Study Short-Form Health Survey (MOS SF - 36), including demographic data, characteristics and amount of loss, social support, health information, and type of Tsunami exposure were recorded.Result:A total of 434 subjects participated in this study. Male was 77%. Married was 67%. Mean age was 33.56 ± 9.26 years old. The QOL scores among members of the Navy or their spouses were lower than the 2006 Thailand normative data (Bangkok) in almost all subscales except physical functioning, bodily pain, and social functioning. The major consequence of the Tsunami was mental health problems. A majority of the survivors who seriously experienced mental problems were female, low education, decreased income, loss of one's family members/loved ones, or property. Bodily pain was the only indicator subscale of QOL which was significant statistically associated with Tsunami exposure.Conclusion:The QOL measurement provided essential information that helped healthcare providers to identify survivors’ needs and outcomes. In addition, the changes in QOL over time after Tsunami disaster might be an effective guideline for health resources allocation. To improve their quality of life, these people required appropriate social support as well as physical and mental health care.

2004 Tsunami: Long-Term Psychological Consequences for Swiss Tourists in the Area at the Time of the Disaster

Most of the data on psychological outcome and the mental health treatment available following natural disasters originate from the indigenous population of the region destroyed. Examining tourists returning from the area affected by the 2004 tsunami presents an opportunity of studying the impact of natural disasters on psychological outcome and mental health treatment in their countries of origin. The aim of the present study was to extend the current knowledge on psychiatric morbidity and potential positive outcomes, as well as subsequent mental health treatment following a natural disaster, based on the results from a sample of home-coming Swiss tourists. Tourists who had been potentially affected by the 2004 tsunami were assessed using the Post-traumatic Diagnostic Scale, the Hospital Anxiety and Depression Scale, and the Post-traumatic Growth Inventory. Outcome variables were related to the degree of tsunami exposure. In addition, mental health treatment before and after the tsunami was assessed. Of the 342 respondents, 55 (16.8%) fulfilled the criteria of post-traumatic stress disorder (PTSD). Evidence of anxiety or depressive disorder was found in 17.8% and 8.0%, respectively. The tsunami victims who had been directly affected showed significantly more symptoms of anxiety, depression and PTSD, as well as post-traumatic personal growth, than tourists who were indirectly affected or unaffected. A total of 12.3% of untreated respondents fulfilled the criteria for PTSD and 38% of respondents who had received psychiatric treatment were still fulfilling PTSD criteria 2(1/2) years after the tsunami. A marked percentage of respondents reported symptoms of PTSD but they remained untreated or were treated insufficiently. We recommend that tourists returning from regions affected by natural disasters be informed about PTSD and that careful screening be given to those found to be at risk of PTSD. An open-door policy of mental health services is particularly needed for tourists returning home who have been affected by large-scale disasters.

Tsunami exposure estimation with land-cover data: Oregon and the Cascadia subduction zone

A Cascadia subduction-zone earthquake has the potential to generate tsunami waves which would impact more than 1000 km of coastline on the west coast of the United States and Canada. Although the predictable extent of tsunami inundation is similar for low-lying land throughout the region, human use of tsunami-prone land varies, creating variations in community exposure and potential impacts. To better understand such variations, land-cover information derived from midresolution remotely-sensed imagery (e.g., 30-m-resolution Landsat Thematic Mapper imagery) was coupled with tsunami-hazard information to describe tsunami-prone land along the Oregon coast. Land-cover data suggest that 95% of the tsunami-prone land in Oregon is undeveloped and is primarily wetlands and unconsolidated shores. Based on Spearman rank correlation coefficients ( r s), correlative relationships are strong and statistically significant ( p < 0.05) between city-level estimates of the amount of land-cover pixels classified as developed (impervious cover greater than 20%) and the amount of various societal assets, including residential and employee populations, homes, businesses, and tax-parcel values. Community exposure to tsunami hazards, described here by the amount and relative percentage of developed land in tsunami-prone areas, varies considerably among the 26 communities of the study area, and these variations relate to city size. Correlative relationships are strong and significant ( p < 0.05) for community exposure rankings based on land-cover data and those based on aggregated socioeconomic data. In the absence of socioeconomic data or community-based knowledge, the integration of hazards information and land-cover information derived from midresolution remotely-sensed imagery to estimate community exposure may be a useful first step in understanding variations in community vulnerability to regional hazards.

The 1856 Djijelli (Algeria) earthquake and tsunami: source parameters and implications for tsunami hazard in the Balearic Islands

Abstract. In 1856, one (or two) destructive earthquake(s) occurred off Djijelli (Algeria) and probably triggered a tsunami in the western Mediterranean Sea. Following recently published results of marine campaigns along the North-Algerian margin, a new source hypothesis for the earthquake has been proposed, and is constituted with a set of three "en échelon" fault segments positioned in agreement with previous studies of this earthquake and with macroseismic data available. The geometrical parameters for this source, in agreement with a Mw = 7.2 earthquake, display an average 40° NW dip, a 80° strike and mean dimensions of 80 km (length) × 20 km (width). A coseismic slip of 1.5 m is consistent with an average convergence rate of about 5–6 mm/yr and a recurrence period of 300–400 years. They are then introduced in the tsunami modelling code to study the propagation across the Mediterranean Sea with a special attention towards the Balearic Islands. A focus on the two major towns, Palma (Majorca) and Mahon (Minorca) Harbours shows that these places are not the most exposed (maximum water heights less than 1 m) by tsunami waves coming from this part of the African margin. Specific amplifications revealed by modelling occur off the southern coast of Minorca and the southeastern coast of Majorca, mostly related to submarine bathymetric features, and are able to produce coastal wave heights larger than 1 to 2 m as offshore Alcalfar (Minorca). A deep submarine canyon southward Minorca leads to the amplification of waves up to two times on both sides of the canyon. However these modellings could not be compared to any historical observations, non-existent for these sites. This work is a contribution to the study of tsunami hazard in western Mediterranean based on modelling, and offers a first assessment of the tsunami exposure in the Balearic Islands.

Thai adolescent survivors 1 year after the 2004 tsunami: A mixed methods study.

This study examined the impact of the 2004 Asian tsunami on 400 Thai adolescents 1 year after the disaster. Quantitative analyses showed that youth behavior problems were positively associated with tsunami experiences and negatively associated with positive family functioning. Tsunami exposure, school connectedness, religious beliefs and practices, and availability of mental health services did not predict behavior problems. Sequential regression analysis was performed with age, gender, tsunami experiences, and family functioning predicting youth behavior problems. In-depth interviews with 40 adolescents revealed many losses and difficulties after the tsunami, including death of parents and school difficulties. Positive aspects of recovery were support from family, peers, and other social networks and increased educational opportunities.

Family context of mental health risk in Tsunami affected mothers: Findings from a pilot study in Sri Lanka

This study investigated direct and indirect influences of Tsunami exposure on mothers' PTSD and depressive symptoms using survey data from 325 Tsunami-affected families living in two villages in southern Sri Lanka. Findings generally support the hypothesized model in that life and property destruction contributed to the PTSD and depressive symptoms of mothers. Detrimental influences of Tsunami exposure also operated through the generation of more proximal secondary Tsunami risks such as post-Tsunami family problems. In addition, religious participation, familism, number of children, intact family status, and community support reduced mothers' depressive symptoms. Finally, intact family status and high religious participation moderated the detrimental influence of Tsunami exposure on mothers' PTSD symptoms. These findings can contribute directly to improving ongoing recovery and reconstruction programs and help to formulate future programs for families affected by the Tsunami and other natural disasters.

Family context of mental health risk in Tsunami-exposed adolescents: Findings from a pilot study in Sri Lanka

Using survey data from 325 Tsunami-exposed adolescents and mothers from two villages in southern Sri Lanka, this pilot study investigated influences of Tsunami exposure and subsequent psychosocial losses on adolescent depressive and post-traumatic stress disorder (PTSD) symptoms. Findings generally support the study hypotheses: disaster exposure (for example experiences of property destruction and deaths of close others) contributes to depressive and PTSD symptoms in adolescents. Findings also show that psychosocial losses associated with Tsunami exposure, such as prolonged displacement, social losses, family losses, and mental health impairment among mothers, contribute to depressive and PTSD symptoms in adolescents. Results suggest that the influence of Tsunami exposure on adolescent mental health operates partially through Tsunami-related psychosocial losses. As expected, positive mother–child relationships provide a compensatory influence on both depressive and PTSD symptoms of adolescents. In addition, high levels of depressive symptoms among mothers increases the detrimental influence of other Tsunami-related psychosocial losses on adolescent mental health. These preliminary findings suggest ways to improve ongoing recovery and reconstruction programs and assist in formulating new programs for families exposed to both the Tsunami and other natural disasters. More importantly, findings from this pilot study emphasize the urgent need for larger systematic studies focusing on mental health following disaster exposure.

Coastal Ecosystems and Tsunami Protection after the December 2004 Indian Ocean Tsunami

An exploratory study was conducted on the role of coastal ecosystems in protecting communities from the December 2004 Indian Ocean tsunami, focusing on mangrove forests on the Andaman coast of Thailand and how well villages were undertaking environmental conservation. Remote sensing analysis identified predisaster mangrove change and postdisaster structural damage and landscape changes. Field data from five sites (20 villages), gathered via the VIEWS™ data collection system, validated and supplemented this analysis. Key informants at several of these villages were also interviewed. A preliminary comparison of villages that otherwise faced similar tsunami exposure suggests that the presence of healthy mangroves did afford substantial protection. Village performance in mangrove conservation and management efforts, and thus the presence of healthy forests, is influenced by both social capital and the design of external aid delivery programs.

Tsunami construction risks in the Mediterranean – outlining Malta's scenario

PurposeTo provide data on the tsunami hazard of the Mediterranean region, to outline the Maltese Islands specific tsunami risks.Design/methodology/approachThe physics of tsunami and the tsunami magnitude scales are first introduced. The Mediterranean tsunami characteristics are introduced by reference to sources (1962‐2003). Following this the Mediterranean tsunami vulnerability assessment is undertaken. This then narrows down to assessing the Maltese tsunami hazards with reference to various newspaper articles, with finally a risk assessment for Malta tsunami exposure calculated.FindingsConsidering the high loss of life occurring in the Indian Ocean catastrophic tsunami, tsunami awareness hazards are to be kept ongoing whilst Malta should form part of an expected European Tsunami Warning System.Practical implicationsPlanning is to consider various options available including tsunami barriers, evacuation paths, buildings with vertical evacuation facilities. It would be more prudent to work with nature by moving all inessential structures further into the interior and to protect the shoreline with suitable vegetation.Originality/valueCreates a Mediterranean/Maltese awareness to tsunami hazards/risks in a highly developed tourist region.