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2015 | Book

Long-Term Recovery from the 2011 Great East Japan Earthquake and Tsunami Disaster Read chapter Read first chapter

Post-Tsunami Hazard

Reconstruction and Restoration

Editors: V. Santiago-Fandiño, Y.A. Kontar, Y. Kaneda

Publisher: Springer International Publishing

Book Series : Advances in Natural and Technological Hazards Research

Part of: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik" , Springer Professional "Wirtschaft"

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About this book

This monograph focuses on a variety of topics related to reconstruction and restoration in post-tsunami conditions. Aspects such as coastal engineering, early warning systems and technological approaches, urban planning and settlements relocation, socio-economic redevelopment and policy, coastal ecosystems and agricultural redevelopment as well as pollution assessment are included. The reader will benefit from the various case-studies drawn from a number of countries hit by the 2004 tsunami in the Indian Ocean and the Great East Earthquake and Tsunami of March 2011 in Japan.

This book will appeal to scientists and scholars, decision makers, students and practitioners interested in post-tsunami reconstruction and restoration processes.

Table of Contents

Frontmatter
Chapter 1. Long-Term Recovery from the 2011 Great East Japan Earthquake and Tsunami Disaster
Abstract
Because national and local governments completed the Recovery Planning process for the areas impacted by the East Japan Earthquake Disaster in 2011, the recovery phase is currently being implemented. The physical recovery of the tsunami-impacted areas considers policies related to land use changes and the relocation of affected people. Due to the periodic tsunamis in the Tohoku area, part of the recovery process is relocating people from tsunami-prone areas. Land use regulations in coastal areas and people’s resettlement to higher ground are usually discussed after each tsunami disaster. However, these policies usually fail because people return to vulnerable areas. This paper discusses the damage suffered from the East Japan Earthquake Disaster in the resettlement areas from the Meiji (1896) and Showa (1933) Sanriku Tsunami disaster based on historical documentation and field survey undertaken in 2011. Four types of damage patterns emerged: (1) No damage: Aneyosi, a well-known location where a stone-monument indicates that villagers should not live below the site, did not sustain damage despite of highest tsunami inundation. (2) Slight damage: Some resettlement sites of the Meiji tsunami, which remained on higher ground, did not suffer major damages. (3) Severely damaged low lands: Resettlements where the community expanded to low land areas sustained significant damage. (4) Major damage: Some sections of the Showa resettlements were badly damaged due to the unexpected scale of the tsunami.
Issues related to recovery after a disaster are discussed based on studies conducted at the Showa resettlement site.
Maki Norio
Chapter 2. Reconstruction Plans and Planning Process After the Great East Japan Earthquake and Tsunami
Abstract
This paper aims at showing the numerous gaps between the ideal concept and reality in the reconstruction process after the Great East Japan Earthquake and the following tsunami within 2 years from the disaster. The gaps are mainly attributable to the misunderstanding or incomprehension of spatial planning by the local government, which puts too much weigh on acceleration of the planning process and lacks in preparation to deal with the disaster in the ordinary time.
Michio Ubaura
Chapter 3. Three Years After a Mega-disaster: Recovery Policies, Programs and Implementation After the Great East Japan Earthquake
Abstract
Since March 11 2011, the national government of Japan has invested significant resources to aid recovery in the Tohoku region, devastated by the Great East Japan Earthquake (GEJE) and tsunami. Thus far, 25 trillion yen (approximately US$ 250 billion) has been committed, a 10-year national Reconstruction Agency has been established to guide the process, and many planning policies and rebuilding programs have been developed and implemented. During this time, four Prefectures and 81 local governments have also crafted recovery plans, and identified national rebuilding programs for use in implementing their plans. The first sites for permanent relocated settlements have been completed, and some residents have already moved into permanent disaster recovery public housing. At the same time, approximately 267,000 people are still displaced and living in temporary housing as of March 2014.
This chapter provides an overview of policies and programs for rebuilding from the GEJE that have a strong emphasis on reducing risk for future tsunamis, along with the awareness of the need for both physical and non-physical aspects of disaster mitigation. Focus is given to describing policies and programs for land use, temporary housing and the current conditions of disaster survivors in regaining stability in their lives. Also, the progress of program implementation and livelihood rebuilding in communities is clarified, to explain the unprecedented challenges and emerging opportunities that affected localities and communities are experiencing due to the unique nature of the tsunami impacts.
Kanako Iuchi, Elizabeth Maly, Laurie Johnson
Chapter 4. Relocation After Tsunamis in the Sanriku Area and the Condition of Fishing Villages Two Years After the 2011 Great East Japan Tsunami
Abstract
The 2011 Great East Japan tsunami severely damaged or destroyed most of the fishing ports and facilities along the Sanriku coast. Reconstruction is ongoing, and a relocation plan has already been enacted. Interviews with fishermen in three fishing villages were performed to obtain reports on current situations as well as opinions and problems. For each village, information regarding reconstruction after historical tsunamis and the 2011 tsunami were obtained, and comparisons were made amongst the target villages. A land ownership problem was found in Tadakoshi village. Moving to high ground was proposed for the first time after the 2011 tsunami in Niranohama village. Housing relocation occurred in some parts of Tadakoshi and Yagawa after historical tsunamis in the Sanriku area, but the whole village will be relocated to high ground in the future, as lessons from the 2011 tsunami revealed that the tsunami inundation area was much larger. In general, all of the villages are still facing problems resulting from land subsidence where the ports are partly submerged during high tide. Although there are some small differences in detail, the three villagers have the same desire to move the entire community to high ground, making high seawalls unnecessary because there will be no more houses on the low land area. Some disagreement regarding the height of seawalls remains between coastal residents and local governments.
Anawat Suppasri, Mari Yasuda, Yoshi Abe, Yo Fukutani, Fumihiko Imamura, Nobuo Shuto
Chapter 5. Lessons Learned from Two Villages in the Tsunami Most Affected Area of Banda Aceh City; A Review of the Housing Reconstruction and the Current State of Village Development
Abstract
This paper discusses two approaches to post-disaster housing reconstruction in Banda Aceh, the Indonesian area that was the most affected by the Indian Ocean Tsunami in 2004. The two villages discussed in this study are Alue Deah Tengoh and Lambung, both located in Meuraxa sub-district. The village of Alue Deah Tengoh represents the common approach to post-disaster reconstruction within in Aceh with the construction of housing carried out by several external benefactors. It is referred to as the donor driven approach. In contrast, the reconstruction of the village of Lambung was based on its community’s involvement. Contrasting these two approaches, this study analyzes time series satellite images, housing and other reconstruction archives. It also conducted site evaluation and depth interview with their leaders in order to evaluate the conditions of each village prior to tsunami as well as its current state of development. Our aim is to unravel the process of housing reconstruction in these respective locations village. Drawing from this analysis, our results evaluate these two distinct approaches to housing reconstruction in post-disaster Aceh. On the one hand, it reveals that the community-based approach adopted in Lambung enabled the successful use of land consolidation (LC) and the total makeover of village layout and housing plot arrangement. On the other hand, our study reveals that the donor approach in Alue Deah Tengoh resulted in a heterogeneous landscape with several types of houses contributing to social inequality and disparity. Moreover, the reconstruction of Alue Deah Tengoh did not include LC and kept the village old layout with its meandering narrow streets and poor accessibility. These features are bond to hinder the upgrading and maintenance of urban utility services as well as the evacuation process during future disasters. In the light of this study, we thus recommend that community driven approach should be implemented in post-disaster reconstruction programs.
Muzailin Affan, Shunichi Koshimura, Fumihiko Imamura, Hizir Sofyan, Sylvia Agustina, Nizamuddin, Nur Fadli
Chapter 6. Accomplishments in the South Coastal Thai Communities After the 2004 Tsunami in the Restoration Process, A Case Study in Ranong Province
Abstract
The 2004 tsunami caused by the great Sumatra earthquake devastated a large amount of the local communities along the coastline of the Andaman Sea in the southern Thailand. Since then most communities have been gradually recovered from this disaster through various restoration processes. This chapter presents a case study of the post-disaster recovery processes for two small local villages: the Nua and the Hat Sai Khao villages in Suk Samran district, Ranong province, compared with those of the government organizations, the Kasetsart University’s Andaman Coastal Research Station for Development that was also hit hard by this tragic incident. The recovery process of these two small villages can be used as proxies for many small local communities in the southern Thailand about how they have adapted themselves to restore their communities back to their normal stages and eventually to have a sustainable immunity to this natural hazard. The tsunami impacts and detailed restoration and reconstruction processes of these two villages are discussed from the day the disaster occurred until recently. It can be concluded that for small local communities, the external supports, either from central government or the private sectors, are as important as the wills of the residents to support themselves. Without the external help, it is extremely difficult for such small local communities in Thailand to get back on their feet within a short time. In addition, the large amount of the funding support must be distributed to the affected communities within a short time in order to provide effective recovery processes. It can be seen for this specific case study that the continuation of the long term support to the affected communities and the participation of the victims in the restoration and reconstruction processes are also very important in order to help the victims restore their lives and to avoid any social problems that may occur in the affected communities in the future.
Passakorn Pananont, Raykha Srisomboon, Wisai Kongkaew, Pralin Kriwichai
Chapter 7. Reconstruction Process and Social Issues After the 1746 Earthquake and Tsunami in Peru: Past and Present Challenges After Tsunami Events
Abstract
Tsunamis, oceanic wave events that are most often triggered by earthquakes at interplate subduction areas, result in damaged infrastructure, ecological disruption and a substantial number of deaths among coastal communities. In recent years, a key concept in the assessment of tsunami events has been resilience, which can be understood as the ability of a group to anticipate risk, limit negative impacts and recover rapidly from a catastrophic event through processes of survival, adaptability, evolution and growth. The term resilience incorporates a dynamic and durable connotation of constant preparedness, not only for the next tsunami event but also for the ensuing process of reconstruction. The reconstruction of a community devastated by a tsunami poses a multiplicity of challenges, including environmental, social, political, scientific, engineering and architectural challenges. In this paper, we first examine a 1746 tsunami event (Mw9.0) that occurred on the coast of Viceroyalty-era Peru and consider the challenges reported during the subsequent reconstruction of a devastated city and port. We contrast those challenges, reported nearly 250 years ago, with analogous challenges observed in more recent tsunami events. The paper concludes with comments on the lessons learned and suggests areas of future research.
Erick Mas, Bruno Adriano, Julio Kuroiwa Horiuchi, Shunichi Koshimura
Chapter 8. The Tsunami Warning System in Thailand: A Part of the Reconstruction Process After the 2004 Indian Ocean Tsunami
Abstract
A disaster early warning system is an important tool to prevent a large number of human casualties from natural disasters such as earthquakes and tsunamis. In Thailand, an early disaster warning system has been established as a part of the reconstruction process after the 2004 Indian Ocean earthquake and tsunami. This chapter focuses on the establishment, development and management process of this early warning system, with particular emphasis on tsunami hazards. This study considers face-to-face interviews with executive officers from the National Disaster Warning Center (NDWC) and the Seismological Bureau of the Thai Meteorological Department (TMD). Moreover, observations of a warning drill conducted in September 2013 in Bangkok, Thailand are also considered. Relevant issues and findings are discussed while providing suggestions for the potential development of early warning systems of a similar nature in other developing countries.
Natt Leelawat, Anawat Suppasri, Fumihiko Imamura
Chapter 9. Effects of the Offshore Barrier Against the 2011 Off the Pacific Coast of Tohoku Earthquake Tsunami and Lessons Learned
Abstract
In this study, the effectiveness of an offshore breakwater for the 2011 off the Pacific Coast of Tohoku Earthquake Tsunami was examined by two-dimensional (2D), quasi three-dimensional (quasi-3D) and three-dimensional (3D) numerical models. First, both 3D numerical models were applied to the behavior of tsunami inundation for Kamaishi Bay in Iwate Prefecture where an offshore deep-water breakwater was installed against an assumed tsunami before 2011. The numerical results indicate 20 % error of maximum inundation height compared with the post-event tsunami survey on the land. It is found that the offshore breakwater significantly reduced the tsunami height on the land. The reduction of tsunami height on the land gave about 30 % tax revenue in comparison with similar locations with or without breakwater. Based on the results the construction and or rebuilding of damaged offshore breakwaters can be considered as a viable option against tsunami particularly in vulnerable areas.
Nobuhito Mori, Nozomu Yoneyama, William Pringle
Chapter 10. A Method to Determine the Level 1 and Level 2 Tsunami Inundation Areas for Reconstruction in Eastern Japan and Possible Application in Pre-disaster Areas
Abstract
After the 2011 tsunami, a new approach to land use planning was introduced and is starting to be applied in some areas of Japan. Depending on the characteristics of the tsunami hazard, an area that is likely to be affected by high-frequency but low-impact tsunamis is identified as a ‘Level 1’ tsunami inundation area. An area that is likely to be affected by low-frequency but high-impact tsunamis is identified as a ‘Level 2’ tsunami inundation area. The countermeasures adopted in the two areas are different. The improved design of physical structures will be used to minimize the medium-to-low impact of tsunamis on people and properties in tsunami inundation Level 1 areas. Because the coverage of the flooded area is much wider in tsunami inundation Level 2 areas, improvements to the evacuation facilities and better education are the major efforts to save lives because man-made structures may not be able to significantly reduce the potential risks. This paper proposes a method to distinguish the boundaries between tsunami inundation Level 1 and 2 areas. We first use numerical simulations to establish a framework that classifies areas as Level 1 or Level 2 in a post-disaster area. Next, we examine the possibility of applying similar techniques to a pre-disaster area. We demonstrate that distinguishing areas of tsunami inundation Level 1 and Level 2 is not only important for the reconstruction of the post-disaster areas but also necessary to mitigate future tsunamis in pre-disaster areas.
Abdul Muhari, Kentaro Imai, Daisuke Sugawara, Fumihiko Imamura
Chapter 11. Effectiveness of Real-Time Near-Field Tsunami Inundation Forecasts for Tsunami Evacuation in Kushiro City, Hokkaido, Japan
Abstract
An algorithm called NearTIF, designed to produce tsunami inundation maps of near-field sites before the actual tsunami hits the shore, was previously developed by the authors. This algorithm relies on a database of precomputed tsunami waveforms at several near-shore locations and tsunami inundation maps from various earthquake fault models. In the event of a great earthquake, tsunami waveforms at the above mentioned near-shore locations are computed on the basis of real-time observation data by use of linear long-wave equations. Simulating these tsunami waveforms takes only 1–3 min on a common personal computer, so the realistic offshore tsunami waveforms can be forecasted. The offshore real-time simulated tsunami waveforms are then compared with precomputed tsunami waveforms in a database to select the site-specific best fault model and the corresponding tsunami inundation map. The best tsunami inundation map is then used as the tsunami inundation forecast. We evaluated the effectiveness of this algorithm in the real world by carrying out a tsunami evacuation drill in Kushiro City, Hokkaido, Japan, involving the city residents. The drill started with the announcement of a tsunami warning, to evacuate the residents to the nearest evacuation building. Approximately 10 min after the announcement, the tsunami inundation forecast map was given to the participants in the drill. The participants found that the use of the tsunami inundation forecast map produced by NearTIF was effective in helping them make better decisions with high confidence during the tsunami evacuation drill. The NearTIF algorithm is recommended for use as part of the reconstruction policy by local authorities to improve the evacuation efficiency, particularly in tsunami-prone areas.
Aditya Riadi Gusman, Yuichiro Tanioka
Chapter 12. Advanced Real Time Monitoring System and Simulation Researches for Earthquakes and Tsunamis in Japan
Abstract
Mega thrust earthquakes generated large tsunamis quite often. Based on lessons learned from the 2004 Sumatra and the 2011 East Japan Earthquakes/Tsunamis, we recognized the importance of real time monitoring on the natural hazards. Monitoring systems using multi kinds of sensors such as the accelerometer, broadband seismometer, pressure gauge, difference pressure gauge, hydrophone and thermometer is indispensable not only for mitigation of damage from earthquakes and tsunamis, but also for understanding of broadband crustal activities around mega thrust earthquake seismogenic zones. Therefore, we have developed the Dense Ocean floor Network for Earthquakes and Tsunamis (DONET) to acquire the seafloor data in real time around the Nankai trough seismogenic zone, southwestern Japan. The first phase of deployment (DONET1) was completed and the second phase (DONET2) is being developed at the time of writing of the manuscript. At the 2011 East Japan Earthquake, DONET1 observatories detected offshore tsunamis 15 min earlier than onshore stations. Furthermore, DONET1 and DONET2 will be expected to monitor silent phenomena such as low frequency tremors and slow earthquakes for the estimation of seismic stage which would occur in the inter-seismic or pre-seismic stage. The recurrence cycle of mega thrust earthquakes, modeling of tsunami inundation and seismic response on buildings and cities are also important in the disaster mitigation programs and related measures. Real-time monitoring data should be integrated with the advanced simulations for precise earthquake and/or tsunami early warnings and rapid estimation of the damages.
Yoshiyuki Kaneda, Narumi Takahashi, Toshitaka Baba, Katsuyoshi Kawaguchi, Eiichiro Araki, Hiroyuki Matsumoto, Takeshi Nakamura, Shinichiro Kamiya, Keisuke Ariyoshi, Takane Hori, Mamoru Hyodo, Masaru Nakano, Jin-Kyu Choi, Shuhei Nishida, Takashi Yokobiki
Chapter 13. Seawall Performance Along Southern Coast of East Japan Impacted by the 2011 Tohoku Tsunami; A Note for the Reconstruction Process
Abstract
This article describes the performance of seawalls in the 2011 Tohoku Tsunami on the basis of tsunami surveys along the southern coastline of East Japan. In Chiba and Ibaraki Prefectures where incident tsunami was slightly higher than the height of seawalls but lower than the backshore dune height, the tsunami was blocked by the presence of the dune as well as the seawalls. Significant flooding damage was developed only in the harbour area as well as in the area around the river mouth. The presence of the water gate at the river mouth appeared to be effective to minimize the flooding. In the south of the Fukushima Prefecture where incident tsunami was 1–3 m higher than the height of seawalls, a clear contrast was observed in the damage of seawalls as well as in the inland damage behind collapsed and survived seawalls, which provided valuable hints for tenacious seawall structure that enhances durability against tsunami overflow. These observations helped to establish a new strategy for tsunami disaster mitigation and thus to promote the reconstruction process on the basis of proper understanding of the limitation and effectiveness of seawalls.
Shinji Sato
Chapter 14. A Consideration Aimed at Improving the Resiliency of Protective Structures Against Tsunami
Abstract
In this paper the effectiveness of breakwaters to provide protection against huge tsunami was considered using numerical simulations. Kamaishi Bay, where large breakwaters had been installed, was selected as the target area, because about half the breakwaters were washed away by the tsunami produced by the Tohoku Earthquake in 2011. Therefore, the effect of breakwater protection against the 2011 tsunami is verified by comparing the different states of damage to breakwaters with numerical simulations. The results show that the protective effect provided by breakwaters against tsunami depends on the rate of opening gap, and suggest that this is an efficient way to improve the resiliency of deeper-region breakwater structures.
Taro Arikawa, Takayuki Oie
Chapter 15. Serious Erosion of the Southern Sendai Coast Due to the 2011 Tohoku Earthquake Tsunami and Its Recovery Process
Abstract
We investigate morphology change of the southern Sendai Coast due to the 2011 Tsunami by analyzing topography and aerial images before and after the tsunami. The results show the characteristics such as erosion in the longshore direction behind seawalls, landward sediment transport during tsunami runup, seaward sediment transport from shore during backwash especially through crevasses of the seawalls, and coastal stabilization by coastal structures such as seawalls, breakwaters and headlands. At the seriously eroded Yamamoto Coast, more than half of the total amount of eroded shore sand above sea level was estimated to be transported seaward due to backwash. After 1 year from the tsunami, the eroded coasts were recovered to form pocket beaches. After another year, the coastal morphology had not changed apparently but seawalls started to be reconstructed. At present, after 3 years from the tsunami, the seawalls with a height of 7.2 m have been reconstructed along the coast. With the reconstruction, the foundation ground of the seawalls has been recovered, but the eroded beaches still remain disappeared. The coast act in Japan was established in 1956 to protect the coast from disasters, and amended in 1999 to also preserve both the coastal environment and its utilization. From the perspective of long-term coastal management, it is strongly required to consider the vision of the future coast.
K. Udo, Y. Takeda, M. Takamura, A. Mano
Chapter 16. Resilience and Vulnerability Analysis for Restoration After Tsunamis and Floods: The Case of Dwellings and Industrial Plants
Abstract
The resilience approach represents a unified and integrated framework for the restoration process following disasters. Under given resilience parameters values, a resilient system is able to recover and be strengthened within a defined recovery period; otherwise, it is a non-resilient system. This chapter considers different structures and focuses on several parameters which govern resilience together with their mechanical vulnerability under various hazards. A new method of theoretically measuring resilience, its link with mechanical vulnerability, and its sensitivity analysis are investigated for dwellings and industrial plants under the effects of flood and tsunami hazards:
  • Non-designed (informal) masonry constructions under the effects of a flooding hazard: vulnerability is estimated after a rapid inspection by qualified engineers. Fragility curves are developed and the structural failure risk is calculated and mapped depending on the intensity of the hazard: water height and flow velocity, in a real case.
  • Structural and non-structural waste generated by flooding: relevant models are adopted and used for predicting expected quantities of waste. The territory may take several years to recover since generated waste may represent several times annual quantities produced under normal circumstances.
  • Coastal industrial plants under the effects of a tsunami hazard: structural failure in tanks results from buoyancy (uplift), overturning, sliding by shear effect, excessive bending, or buckling. Vulnerability and fragility curves are developed for various tanks of small and large sizes.
Ahmed Mebarki, Bruno Barroca
Chapter 17. Tsunami and Environmental Pollution Hazards: A Note for the Restoration Process
Abstract
The large destruction of industrial facilities, processing factories and urban areas by the 2011 tsunami along the northeast coast of Tohoku Region (Japan) resulted in extensive contamination in most of the flooded areas and coastal waters; an enormous amount of mixed debris and radiation compounded these problems, creating both potential environmental and human health hazards which should be assessed throughout the reconstruction and the restoration process.
Open-air temporary debris storage sites lacking sufficient insulation have likely contaminated air, soil, marine and freshwater bodies with hazardous chemicals along certain areas in Tohoku. Moreover, construction wooden debris treated with biocides, weathering fixatives and fire retardants accumulated in the sites along the region have likely leached a host of toxic compounds including metals, arsenic and other hazardous substances posing a threat to soil and water sources, including groundwater.
As part of the region’s reconstruction process, the potential short, medium and long-term environmental toxicity and damage to key ecosystems, flora and fauna as well as the contamination and impact on commercial resources, soil and water require careful assessment.
This chapter provides a general overview of the potential contamination that may have occurred as a result of the tsunami of March 2011 along the Tohoku Region in Japan. Emphasis is made in the Miyagi prefecture looking at the contamination originated from the storage and management of wooden debris and other sources as well as some of its related environmental consequences.
Vicente Santiago-Fandiño, Mi Hyung Kim
Chapter 18. The Agri-Reconstruction Project and Rapeseed Project for Restoring Tsunami-Salt-Damaged Farmland After the GEJE – An Institutional Effort
Abstract
The Graduate School of Agricultural Science, Tohoku University, launched an Agri-Reconstruction Project in 2011 immediately after the March 11 Great East Japan Earthquake disaster, and this continues to date. The project’s objective is to support the agricultural, forestry and fisheries reconstruction process in the tsunami disaster area. The activities have been implemented through more than 40 research projects along the Tohoku region including the Rapeseed Project for Restoring Tsunami-Salt-Damaged Farmland.
Immediately after the disaster, damaged farmlands were surveyed and salt-tolerant rapeseed varieties from Brassicaceae and related species were used to restore the soil. The plants came from the gene bank developed at the Graduate School of Agricultural Science, and were planted on damaged farmland in Sendai, Iwanuma and Higashi Matsushima cities. The varieties used to restore the soil depended on the specific damage.
As part of the project, the production and sale of edible as well as fuel oil obtained from rapeseed plants was organized in coordination with the Miyagi Prefecture Sendai City government, a number of private companies and other partners. This enterprise continues to date.
Besides using the salt-tolerant varieties of Brassicaceae plants in tsunami-damaged fields they are also used overseas in the rehabilitation of salt-damaged farmlands.
Yutaka Nakai, Takeshi Nishio, Hiroyasu Kitashiba, Masami Nanzyo, Masanori Saito, Toyoaki Ito, Michiaki Omura, Miyuki Abe, Yukie Ogushi
Chapter 19. Observations of Natural Recruitment and Human Attempts at Mangrove Rehabilitation After Seismic (Tsunami and Earthquake) Events in Simeulue Island and Singkil Lagoon, Aceh, Indonesia
Abstract
The December, 2004 tsunami and March 2005 earthquake along the Sunda Megathrust off the Western Coast of Aceh, Sumatra, Indonesia not only resulted in catastrophic losses of life and livelihood, but also changed the very shape of the land and coast. The effects of this rapid change in coastal geomorphology are well expressed in a pair of locations, the remote Island of Simeulue, relatively unknown even in Indonesia before the tsunami, and the district of Singkil, which includes a mainland section as well as the Banyak (Many) Islands. Simeulue and Singkil effectively straddle the Sunda Megathrust, yet experienced the cumulative effects of the tsunami and earthquakes differently, with Simeulue Island undergoing seismic uplift while coastal mainland Singkil subsided. After the seismic events, at least 163 separate institutions (government agencies, local and international non-governmental organizations) planned and implemented mangrove rehabilitation activities in Aceh, including over a dozen in Simeulue and Singkil districts. (Brown and Yuniati 2008) Despite a great deal of commitment from such organizations to bringing back mangroves in the affected areas, the majority of the rehabilitation attempts, which mainly relied on hand planting methods, failed to restore mangrove forests. All the while, mangroves were naturally recruiting seismically repositioned intertidal surfaces, and growing well. Near to total mortality was observed in 6 out of 7 planting sites in the two districts, while recruitment rates, stem densities and species diversity in nearby intertidal zones indicated that natural recovery was well underway. When comparing the “success” of natural recovery versus planted sites, we see that practitioners are still faced with significant challenges. This paper makes the case that observation and monitoring of natural regeneration, and calculation of rates of recruitment after a major disturbance event is equally or more important than mangrove planting, from not only ecological but also social and economic points of view.
Ben Brown, Woro Yuniati, Rio Ahmad, Iona Soulsby
Backmatter
Metadata
Title
Post-Tsunami Hazard
Editors
V. Santiago-Fandiño
Y.A. Kontar
Y. Kaneda
Copyright Year
2015
Electronic ISBN
978-3-319-10202-3
Print ISBN
978-3-319-10201-6
DOI
https://doi.org/10.1007/978-3-319-10202-3