scholarly journals THE EXISTENCE OF COASTAL FOREST, ITS IMPLICATION FOR TSUNAMI HAZARD PROTECTION, A CASE STUDY: IN CILACAP-CENTRAL JAVA, INDONESIA

2016 ◽  
Vol 30 (1) ◽  
pp. 23 ◽  
Author(s):  
Yudhicara Yudhicara
Keyword(s):  
Cocos Nucifera ◽  
Tsunami Hazard ◽  
Coastal Protection ◽  
Casuarina Equisetifolia ◽  
Coastal Forest ◽  
Southern Coast ◽  
Coastal Forests ◽  
Tsunami Height ◽  
Tsunami Waves ◽  
Hazard Potential

The southern coast of Java which is facing to the Indian Ocean has many of natural hazard potential come from the sea. Since 2006 tsunami impacted the southern coast of Java, and caused severely damage especially along the coast of Cilacap (1-7,7 m run up height). People commit to do greening the beach by planting suitable plants such as a Casuarina equisetifolia, Terminalia catappa, and Cocos nucifera. This paper discusses the existence of coastal forests in Cilacap coastal area, their potential ability as a coastal protection from the tsunami wave which cover the density, diameter, height, age, and other parameters that affects the coastal defence against tsunami waves. Some experiences of tsunamis that have occurred, indicating that the above parameters linked to the ability of vegetation to act as a natural barrier against tsunamis. In the case of sandy beaches, such as in Cilacap, Pandanus odorarissimus has more effectiveness than other trees due to its hanging roots that can withstand the tsunami height less than 5 m, able to withstand debris and can withstand the scouring effects of tsunami waves, while Casuarina equisetifolia along Cilacap beaches more dominant than other trees, so it is recommended to increase the diversity of plants as well as increase the density and tree placement setting. By field measurement in order to get parameter applied to some graphs, Cilacap coastal forest does not enough capability for tsunami barrier reflected to the tsunami height experience in this region. Ages could be the important parameter in order to have bigger diameter trunk, higher trees height, and high resistance capacity againts tsunami hazard potential. Compare to Kupang, East Nusa Tenggara, Cilacap coastal forest still young and need some more years to make trees ready act as tsunami reduction. Keywords: Cilacap coastal forest, Kupang, tsunami, vegetation parameters. Pantai Selatan Jawa yang berhadapan dengan Samudera Hindia, memiliki banyak potensi mengalami bahaya yang datang dari lautan. Selama tahun 2006, Tsunami telah menimpa sebagian pantai selatan Jawa dan menyebabkan banyak kerusakan parah terutama di sepanjang Pantai Cilacap (tinggi gelombang 1-7,7 m). Masyarakat melakukan penghijauan pantai dengan menanam sejumlah pohon yang sesuai dengan kondisi pantai, seperti pohon cemara pantai (Casuarina equisetifolia), ketapang (Terminalia cattapa) dan kelapa (Cocos nucifera). Tulisan ini membahas penyebaran hutan pantai di wilayah pantai Cilacap, kemampuan dan potensi hutan tersebut sebagai pelindung alami pantai dari bahaya gelombang tsunami, yang terdiri dari kerapatannya, diameter, tingginya, umur, dan parameter lainnya yang mempengaruhi daya tahan pantai terhadap gelombang tsunami. Beberapa pengalaman mengenai kejadian yang telah terjadi, memperlihatkan bahwa parameter tersebut di atas mempengaruhi kemampuan tanaman sebagai penahan alamiah terhadap tsunami. Untuk kondisi pantai berpasir seperti Cilacap, tanaman pandan pantai lebih efektif dibandingkan dengan tanaman lainnya, dikarenakan akarnya yang dapat menahan tinggi gelombang kurang dari 5 m, selain itu akar tersebut dapat menahan material dan erosi vertikal gelombang tsunami, sementara di sepanjang pantai Cilacap, tanaman cemara pantai (Casuarina equisetifolia) lebih dominan dibandingkan tanaman lainnya. Kondisi ini dapat direkomendasikan untuk tetap dipertahankan bahkan ditambah jumlahnya. Di lapangan dilakukan pengukuran parameter tanaman pantai dan hasilnya diplot dalam bentuk grafik dan diaplikasikan dalam grafik yang dibuat berdasarkan hasil penelitian terhadap tsunami di beberapa tempat di dunia terutama di Jepang. Berdasarkan tinggi gelombang maksimum yang pernah terjadi di daerah ini (7,7 m), terlihat bahwa hutan pantai Cilacap belum cukup mampu bertindak sebagai penahan gelombang tsunami. Umur merupakan parameter penting agar pohon memiliki diameter yang besar, pohon yang cukup tinggi dan daya tahan terhadap potensi bahaya tsunami. Dibandingkan dengan hutan pantai di Kupang, Nusa Tenggara Timur, hutan pantai di Cilacap relatif masih muda dan membutuhkan beberapa tahun lagi untuk dapat memperkecil resiko yang ditimbulkan oleh bahaya tsunami. Kata kunci: Hutan pantai Cilacap, Kupang, tsunami dan parameter vegetasi.

Implications of Local Sources to Probabilistic Tsunami Hazard Analysis in South Chinese Coastal Area

2017 ◽  
Vol 11 (01) ◽  
pp. 1740001 ◽  
Author(s):  
Yefei Ren ◽  
Ruizhi Wen ◽  
Peng Zhang ◽  
Zhibo Yang ◽  
Rong Pan ◽  
...  
Keyword(s):  
Coastal Area ◽  
Hazard Analysis ◽  
Earthquake Magnitude ◽  
Tsunami Hazard ◽  
Southern Coast ◽  
Tsunami Waves ◽  
Manila Trench ◽  
Local Sources ◽  
Regional Source ◽  
Probabilistic Tsunami Hazard Analysis

The South China Sea is recognized as an area at high risk of tsunamis. The Manila Trench has long been considered as the regional source of tsunamis that might affect Chinese coastal areas, and considerable analysis of the tsunami hazard has been conducted in this area. However, there has been no consideration of other potential local sources near the coastal area. Thus, the locations of local potential tsunami sources (PTSs) along the southern coast of China and the evaluation of their impact on tsunami hazard assessment require investigation. We identified eight local PTSs for given seismic activity parameters. For the probabilistic tsunami hazard analysis (PTHA), the lower-limit earthquake magnitude was determined as 7.0, based on numerical simulation of tsunami scenarios. Six measured sites in the Pearl River Estuary and Taiwan Strait were selected for PTHA, which were referenced to Macao, Hong Kong, Daya Bay, Shantou, Xiamen, and Quanzhou. The annual rate of tsunami waves exceeding a given height [Formula: see text] was calculated for each site. The results show that the upper-limit earthquake magnitude and the relative geographical positions of the measured site of interest and the PTS are two of the most important factors in the PTHA computation. The probabilities of tsunami waves exceeding a given height [Formula: see text] within 100 years and their return periods were calculated for each site. The results show that the probability of [Formula: see text][Formula: see text]m within 100 years is 30–40% in Xiamen and Quanzhou but 5–10% in Macao and Hong Kong. If the Manila Trench were considered as a regional source, these probabilities would be higher. It is concluded that the tsunami hazard on the southern coast of China is very high and that both regional and local PTSs should be included in any future PTHA.

scholarly journals TSUNAMI HAZARD AND DESIGN OF COASTAL STRUCTURES

1976 ◽  
Vol 1 (15) ◽  
pp. 130
Author(s):  
George Pararas-Carayannis
Keyword(s):  
Tsunami Wave ◽  
Time History ◽  
Tsunami Hazard ◽  
Wave System ◽  
Tsunami Generation ◽  
Coastal Structures ◽  
Tsunami Height ◽  
Tsunami Propagation ◽  
Coastal Site ◽  
Tsunami Waves

Damage of coastal structures by tsunamis results by the direct and indirect action of hydrostatic and dynamic pressures, foundation failures, overtopping and flooding. Reliable assessment of the potential tsunami hazard at a coastal site and adequate engineering design of critical structures require analysis and understanding of all aspects of a tsunami system leading to its terminal behavior. Description of the space-time history of tsunami waves generated by impulsive disturbances require consideration of events and processes in the following regimes: (a) generation; (b) propagation and dispersion; and (c) termination. Processes and events in each regime during the development of a tsunami are under their own unique hydrodynamic constraints but are dependent on what has preceeded. In predicting tsunami wave characteristics at some distance from the generating source, the error structure may be pyramidal. Essential to any method of tsunami prediction at a distant or a nearby coast will be the full consideration and study of tsunami generative mechanisms. If the tsunami generation mechanics cannot be deduced with a reasonable degree of accuracy, it is not likely that the tsunami terminal aspects will be reliably predicted. Prediction of tsunami height at a distant or at a nearby coast requires knowledge of the magnitude and type of ground displacements in the tsunami generating area and of the characteristics of the surface waves resulting from such action. Although all mechanisms involved during tsunami generation are not fully understood, it is possible to obtain a suitable tsunami initiating function through the use of experimental data, historical data, and established empirical relationships, for each type of generating mechanism. Reliable computation of the tsunami propagation effects over and across the ocean can be obtained with proper modeling to provide an adequate description of the tsunami energy flow through the use of physical and numerical studies. Similarly, the terminal aspects and nearshore modification of the tsunami wave system can be approximated to provide the engineering criteria necessary for the assessment of the potential tsunami hazard at a coastal site.

scholarly journals Analysis of private natural heritage reserves as a conservation strategy for the biodiversity of the cocoa region of the southern State of Bahia, Brazil

2010 ◽  
Vol 34 (4) ◽  
pp. 699-711 ◽  
Author(s):  
Alexandre Schiavetti ◽  
Haydee Torres de Oliveira ◽  
Alene da Silva Lins ◽  
Pablo Santana Santos
Keyword(s):  
Forest Succession ◽  
Conservation Strategy ◽  
Conservation Strategies ◽  
Coastal Forest ◽  
Coastal Forests ◽  
Conservation Areas ◽  
Buffer Zones ◽  
Southern State ◽  
Private Organizations ◽  
Environmental Agencies

Brazil was the first country in Latin America to establish and regulate this type of reserve, and there are currently more than 700 Private Nature Heritage Reserves (RPPN in Portuguese) officially recognized by either federal or state environmental agencies. Together, these RPPN protect more than a half million hectares of land in the country. The coastal forests in the southern part of Bahia State extend 100 to 200 km inland, gradually changing in physiognomy as they occupy the dryer inland areas. The coastal forest has been subjected to intense deforestation, and currently occupies less than 10% of its original area. For this work the creation processes of the RPPN were consulted to obtain the data creation time, size of property, the condition of the remaining forest, succession chain and the last paid tax. After that, interviews with the owners were made to confirm this data. Sixteen RPPN have been established in this region until 2005. Their sizes vary from 4.7 to 800 ha. Ten of these RPPN are located within state or federal conservation areas or their buffer zones. In spite of the numerous national and international conservation strategies and environmental policies focused on the region, the present situation of the cocoa zone is threatening the conservation of the region's natural resources. The establishment of private reserves in the cocoa region could conceivably improve these conservation efforts. This type of reserve can be established under a uniform system supported by federal legislation, and could count on private organizations.

scholarly journals Using remote sensing to assess tsunami-induced impacts on coastal forest ecosystems at the Andaman Sea coast of Thailand

2010 ◽  
Vol 10 (4) ◽  
pp. 729-745 ◽  
Author(s):  
H. Roemer ◽  
G. Kaiser ◽  
H. Sterr ◽  
R. Ludwig
Keyword(s):  
Remote Sensing ◽  
Forest Ecosystems ◽  
Ground Truth ◽  
Andaman Sea ◽  
Coastal Forest ◽  
Coastal Forests ◽  
Change Detection Algorithms ◽  
Damage Maps ◽  
2004 Tsunami ◽  
Sea Coast

Abstract. The December 2004 tsunami strongly impacted coastal ecosystems along the Andaman Sea coast of Thailand. In this paper tsunami-induced damage of five different coastal forest ecosystems at the Phang-Nga province coast is analysed with a remote sensing driven approach based on multi-date IKONOS imagery. Two change detection algorithms, change vector analysis (CVA) and direct multi-date classification (DMC), are applied and compared regarding their applicability to assess tsunami impacts. The analysis shows that DMC outperforms CVA in terms of accuracy (Kappa values for DMC ranging between 0.947 and 0.950 and between 0.610–0.730 for CVA respectively) and the degree of detail of the created change classes. Results from DMC show that mangroves were the worst damaged among the five forests, with a 55% of directly damaged forest in the study area, followed by casuarina forest and coconut plantation. Additionally this study points out the uncertainties in both methods which are mainly due to a lack of ground truth information for the time between the two acquisition dates of satellite images. The created damage maps help to better understand the way the tsunami impacted coastal forests and give basic information for estimating tsunami sensitivity of coastal forests.

A multi-scenario assessment of the seismogenic tsunami hazard for Bangladesh

2019 ◽  
Vol 11 (2) ◽  
pp. 156-168
Author(s):  
Janaka J. Wijetunge
Keyword(s):  
Subduction Zones ◽  
Submarine Canyon ◽  
Tsunami Hazard ◽  
Seismic Zone ◽  
Tsunami Propagation ◽  
Content Type ◽  
Arrival Times ◽  
Tsunami Waves ◽  
Scenario Assessment ◽  
Seismic Scenarios

Purpose This paper aims to describe a multi-scenario assessment of the seismogenic tsunami hazard for Bangladesh from active subduction zones in the Indian Ocean region. Two segments of the Sunda arc, namely, Andaman and Arakan, appear to pose a tsunamigenic seismic threat to Bangladesh. Design/methodology/approach High-resolution numerical simulations of tsunami propagation toward the coast of Bangladesh have been carried out for eight plausible seismic scenarios in Andaman and Arakan subduction zones. The numerical results have been analyzed to obtain the spatial variation of the maximum tsunami amplitudes as well as tsunami arrival times for the entire coastline of Bangladesh. Findings The results suggest that the tsunami heights are amplified on either side of the axis of the submarine canyon which approaches the nearshore sea off Barisal in the seaboard off Sundarban–Barisal–Sandwip. Moreover, the computed tsunami amplitudes are comparatively higher north of the latitude 21.5o in the Teknaf–Chittagong coastline. The calculated arrival times indicate that the tsunami waves reach the western half of the Sundarban–Barisal–Sandwip coastline sooner, while shallow water off the eastern half results in a longer arrival time for that part of the coastline, in the event of an earthquake in the Andaman seismic zone. On the other hand, most parts of the Chittagong–Teknaf coastline would receive tsunami waves almost immediately after an earthquake in the northern segment of the Arakan seismic zone. Originality/value The present assessment includes probabilistic measures of the tsunami hazard by incorporating several probable seismic scenarios corresponding to recurrence intervals ranging from 25 years to over 1,000 years.

Tsunami Hazard of the Caspian Sea

2021 ◽  
Author(s):  
Alisa Medvedeva ◽  
Igor Medvedev
Keyword(s):  
Sea Level ◽  
Caspian Sea ◽  
Tsunami Hazard ◽  
Seismic Sources ◽  
Deterministic Approach ◽  
The Caspian Sea ◽  
Tsunami Waves ◽  
The Mean ◽  
Run Up ◽  
Sea Coast

<p>A regional model of tsunami seismic sources in the zone of the Main Caucasian thrust has been developed. The parameters of probable models of seismic sources and their uncertainties were estimated based on the available data on historical earthquakes and active faults of the region. The scenario modeling technique was used for the tsunami zoning of the Caspian Sea coast. The time period covered by the model catalog of earthquakes used to calculate the generation and propagation of tsunamis is about 20 000 years, which is longer than the recurrence periods of the strongest possible earthquakes. The recurrence graphs of the calculated maximum tsunami heights for the entire sea coast were plotted. On their basis, the maximum heights of tsunami waves on the coast were calculated with recurrence periods of 250, 500, 1000 and 5000 years and the corresponding survey maps of the tsunami zoning of the Caspian Sea were created. The algorithm for calculating the tsunami run-up on the coast is improved, taking into account the residual (postseismic) displacements of the bottom and land relief. Estimates of tsunami hazard for the coast near the city of Kaspiysk were carried out: within the framework of the deterministic approach, the maximum wave heights and run-up distance were calculated. It is shown that the deterministic approach slightly overestimates the maximum heights of tsunami waves with certain return periods. It is shown that changes in the mean sea level can affect the features of the propagation of tsunami waves in the Caspian Sea. Thus, at an average sea level of -25-26 m, the Kara-Bogaz-Gol Bay is linked with the entire sea through a narrow strait. It leads to the propagation of tsunami waves into the water area of the bay and a decrease in wave height on the eastern coast of the sea. When the mean sea level decreases below -27 m, the positive depths in the strait disappear and water exchange through the strait stops, and the wave height in this part of the sea increases.</p>

A scenario-based assessment of the tsunami hazard in Palermo, northern Sicily, and the southern Tyrrhenian Sea

2020 ◽  
Vol 500 (1) ◽  
pp. 63-80 ◽  
Author(s):  
Jack Dignan ◽  
Aaron Micallef ◽  
Christof Mueller ◽  
Attilio Sulli ◽  
Elisabetta Zizzo ◽  
...  
Keyword(s):  
Wave Height ◽  
Near Field ◽  
Mass Movement ◽  
Tsunami Hazard ◽  
Small Scale ◽  
Maximum Height ◽  
Northern Coast ◽  
Tyrrhenian Sea ◽  
Worst Case ◽  
Tsunami Waves

AbstractPalermo is a populous city situated on the northern coast of Sicily, bordered by the Tyrrhenian Sea. This central part of the Mediterranean Sea features dramatic bathymetry, numerous subaqueous landslides and is also the epicentre to many subaqueous earthquakes. As such, the region is an area prone to tsunamis. This investigation uses the Cornell Multi-Grid Coupled Tsunami (COMCOT) tsunami modelling package to simulate five near-field landslides, and five near-field earthquakes regarded as worst-case credible scenarios for Palermo. The seismic simulations produced waves on a very small scale, the largest being c. 5 cm at its maximum height, and none of the earthquake-generated tsunami waves produced any measurable inundation. The landslide simulations produced larger waves ranging from 1.9 to 12 m in maximum height, two of which resulted in inundation in areas surrounding the Port of Palermo. Sensitivity analysis identified that fault width and dislocation as well as landslide-specific gravity did have significant influence over maximum wave height, inundation and maximum run-up wave height. There are methodological issues limiting the extent to which this study forms a comprehensive tsunami hazard assessment of Palermo, such as gaps in bathymetric data, computational restrictions and lack of a probabilistic element. These issues are counteracted by the fact that this study does serve as a robust first step in identifying that landslides in the region may produce larger tsunami waves than earthquakes, and that the directionality of mass movement is critical in landslide-driven tsunami propagation in the southern Tyrrhenian region.

Vegetation Change in the Coastal-Lowland Rainforest at Avai'o'vuna Swamp, Vava'u, Kingdom of Tonga

2005 ◽  
Vol 64 (3) ◽  
pp. 451-459 ◽  
Author(s):  
Patricia L. Fall
Keyword(s):  
Vegetation Change ◽  
Coastal Wetland ◽  
Cocos Nucifera ◽  
Habitat Destruction ◽  
Forest Trees ◽  
Coastal Forest ◽  
Sediment Record ◽  
Marine Clay ◽  
Coastal Lowland ◽  
Lowland Rainforest

AbstractAvai'o'vuna Swamp, a small coastal wetland in Vava'u, Kingdom of Tonga, produced a 4500-year pollen and sediment record. Results are: (1) a mid-Holocene sea level highstand is confirmed for Tonga between about 4500 and 2600 14C yr B.P.; marine clay contains pollen from mangroves (Rhizophora mangle), coastal forest trees (Barringtonia asiatica and Cocos nucifera), and rainforest trees (Alphitonia, Rhus, Hedycarya and Calophyllum). (2) Microscopic charcoal first appeared at 2600 14C yr B.P., coincident with the arrival of Polynesians. (3) Cocos, Pandanus, Excoecaria, Macaranga, and Elaeocarpaceae pollen reflects the establishment of a mixed coastal-lowland rainforest in the last 2500 years. (4) The loss of Hedycarya, Elaeocarpus, Calophyllum, and Guettarda and the reduction of Terminalia and taxa in the Papilionaceae family by about 1000 years ago may be due to habitat destruction and the loss of dispersal capabilities of some species through the extinction of the two largest pigeons in Tonga.

Formation forest fitotsenozov Volga River right banks

10.12737/3833 ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. 149-152 ◽  
Author(s):  
Ульданова ◽  
Railya Uldanova
Keyword(s):  
Forest Ecosystems ◽  
Biological Diversity ◽  
Jaccard Coefficient ◽  
Coastal Forest ◽  
Coastal Forests ◽  
Natural Habitats ◽  
Volga River ◽  
Floristic Similarity ◽  
Α Diversity ◽  
Mixed Grass

The coastal forests, presented by valuable deciduous and coniferous forests, grow in the northeastern and eastern parts of the Volga region of the Republic of Tatarstan, skirting the high right bank of the Volga River. They contribute to the maintenance of biological diversity in nature. The study of the formation of coastal forest phytocenoses, their species diversity and the modern state is now urgent work, and development activities for the conservation of natural habitats of plants, improve the sustainability of forest ecosystems are perspective direction. According to research of the forests of the right bank of the river Volga, we present the structure of coastal forest ecosystems. The association of forest ecosystems to the various elements of the relief was installed. The types of soil and litter were presented. The estimation of α-diversity of vascular herbaceous plants and ß-diversity of the studied forest ecosystems were reported. The largest number of species of vascular plants in coastal forests are: oak plant communities; a second group includes birch plants, pine and willow; the third group - the lime and larch; the fourth group - maple plant communitie. The ß-diversity index (Whittaker’s index) of plants in the studied forests varies between 2.2-6.8. The Jaccard coefficient of floristic similarity between forest ecosystems varies from 0.01 to 0.30, which confirms the diversity of generated by coastal forest ecosystems. The greatest diversity of plants was found in forests of ash and mixed grass, mixed grass willow, oak and lime-grove, maple, ash and mixed grass larches, birch wood. The forestry activities in coastal areas should be aimed at creating productive, sustainable forest ecosystems with a rich biodiversity of flora and fauna.

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