DOCSLIB.ORG

Age Estimates of Coastal Terraces in the Andaman and Nicobar Islands and Their Tectonic Implications

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Age Estimates of Coastal Terraces in the Andaman and Nicobar Islands and Their Tectonic Implications Tectonophysics 455 (2008) 53–60 Contents lists available at ScienceDirect Tectonophysics journal homepage: www.elsevier.com/locate/tecto Age estimates of coastal terraces in the Andaman and Nicobar Islands and their tectonic implications Kusala Rajendran a,⁎,1, C.P. Rajendran b, Anil Earnest b,2, G.V. Ravi Prasad c, K. Dutta c, D.K. Ray c, R. Anu b a Centre for Earth Sciences, Indian Institute of Science, Bangalore 560 012, India b Centre for Earth Science Studies, Trivandrum, 695031, India c Institute of Physics, Sachivalaya Marg, Bhubaneswar, 751005, India ARTICLE INFO ABSTRACT Article history: The great Indian Ocean earthquake of December 26, 2004 caused significant vertical changes in its rupture Received 4 July 2007 zone. About 800 km of the rupture is along the Andaman and Nicobar Islands, which forms the outer arc Received in revised form 30 April 2008 ridge of the subduction zone. Coseismic deformation along the exposed land could be observed as uplift/ Accepted 6 May 2008 subsidence. Here we analyze the morphological features along the coast of the Andaman and Nicobar Islands, Available online 13 May 2008 in an effort to reconstruct the past tectonics, taking cues from the coseismic effects. We obtained radiocarbon dates from coastal terraces of the island belt and used them to compute uplift rates, which vary from Keywords: − 1 − 1 −1 Seismicity and tectonics 1.33 mm yr in the Little Andaman to 2.80 mm yr in South Andaman and 2.45 mm yr in the North Subduction zones Andaman. Our radiocarbon dates converge on ∼600 yr and ∼1000 yr old coastal uplifts, which we attribute Tsunami to the level changes due to two major previous subduction earthquakes in the region. Coastal terrace © 2008 Elsevier B.V. All rights reserved. Earthquake Age dating 1. Introduction finding discernible fossil records. This paper presents results of our preliminary studies on coral terraces along the Andaman and Nicobar Defining the intervening processes during the successive stages of Islands, (here after abbreviated as A&N Islands), within the rupture earthquake cycles is a useful means of characterizing interseismic zone of the 2004 great Sumatra earthquake. In combination with behavior of active fault zones, thereby enabling long-term forecast. other geologic evidence, they serve as proxies of past tectonics. Where faults and geomorphic features are exposed on land, these Coseismically uplifted or subsided shorelines are known to serve as studies are relatively easy, but due to the general lack of exposure of paleogeodetic markers of Holocene coastal tectonism (Taylor et al., fault traces, they are difficult for subduction zones (see Sieh, 1981, for a 1980; Vita-Finzi, 1981; Lajoie, 1986). It should, however, be noted that review). Great earthquakes generate tsunamis that travel across isolating the influence of eustatic sea level processes on the oceans, affecting global communities, and historical records often development of coastal terraces may not be easily done in many document inundations by the sea caused by such events. In countries areas. But, we place a higher confidence on our results because of the such as Greece, Italy and Japan, the historical tsunami records stretch predominant role of tectonism in the A&N Islands in shaping the back to a few thousand years and these contain information useful to constituent coastal landforms. Similar attempts on the records of reconstruct earthquake/tsunami histories (Atwater et al., 2005; coastal uplift in other emergent shorelines to determine the long-term Cisternas et al., 2005, for example). In regions like the United States spatial and temporal characteristics of large subduction zone earth- where interseismic intervals are much longer than the documented quakes provide further rationale for our studies (e.g. Plafker and history, the reconstruction of tsunami history has to be based Rubin, 1978; Matsuda et al., 1978; Berryman et al., 1989; Ota and primarily on geological records (e.g. Atwater, 1987, 1992). Settings in Yamaguchi, 2004; Natawidjaja et al., 2004). Further, where precise the tropics, characterized by higher level of human activities, tropical measurements are possible, coastal subsidence and uplift of the storm surges and poor preservation potential add to the challenges of tectonically active zones are also used to infer fault slip parameters and model coseismic rupture (e.g. ten Brink et al., 2006; Shennan and Hamilton, 2006) and tsunami generation (e.g. Cummins, 2007). The ⁎ Corresponding author. Tel.: +91 80 2293 2633. A&N group of islands accommodated about 800-km-length of the E-mail address: [email protected] (K. Rajendran). rupture (Lay et al., 2005) and we believe that as the outer arc of the 1 Formerly at Centre for Earth Science Studies, Trivandrum, India, 695031. 2 Currently at Centre for Mathematical Modelling and Computer Simulation, subduction zone, this region is likely to preserve evidence of past Bangalore, India 560037. tectonic movements. The coseismic elevation changes caused by the 0040-1951/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.tecto.2008.05.004 54 K. Rajendran et al. / Tectonophysics 455 (2008) 53–60 2004 earthquake provide cues in identifying older features formed the outer ridge lies along the trace of the West Andaman Fault. Our through similar events. In this paper we present data on elevated investigations in this paper are restricted to some of the accessible terraces on the A&N group of islands and use them to compute the islands along the western margins of the outer arc ridge, where step- long-term uplift rates. like coral terraces are observable along the coast. The A&N region has experienced large earthquakes in the past; of 2. Morphology, tectonic features and major earthquakes those in the historical record, only the 1881 (Mw 7.9) and 1941 (Mw 7.7) events are important in terms of their sizes, but neither of The A&N group of islands form part of the outer arc ridge of the these produced significant tsunamis (Ortiz and Bilham, 2003; northern segment of the Andaman–Sunda subduction zone (Fig. 1A). Rajendran et al., 2007). These earthquakes are inferred to have Tectonic evolution and salient morphological features are discussed involved smaller ruptures (Fig. 2A). In a recent review based on by Curray (2005). Curray describes the basic structure of the historical records, Dominey-Howes et al. (2006) have collated details Andaman–Nicobar ridge, the accretionary prism of the subduction of Indian Ocean tsunamis since B.C. 326; their study does not provide zone, as an imbricate stack of eastward dipping fault slices and folds. any information to suggest the occurrence of any past events The younger series of rocks, termed as the Archipelago Series, cap comparable to the 2004 tsunami. After the 2004 event, there have these imbricate stacks and they consist typically of limestone, formed been more efforts to search for evidence of past events. In a recent from coral and shell sands. study, Cummins (2007) modeled the rupture parameters and the A section along 11°N parallel (Fig. 1A, B) shows the morphological tsunami generation, based on observations of landform changes. features typical of subduction zones—the outer arc (Andaman and Earthquakes of magnitude ∼8 or smaller are also likely to cause Nicobar Ridge), forearc basin (West Basin, Invisible Bank), volcanic arc morphological changes, but they will be spatially restricted. The ability (Barren, Narcondum) and the backarc basin (Central Andaman basin, to distinguish morphologic changes caused by such earthquakes from East basin). Curray (2005) mentions two normal faults (Diligent Fault, those affecting larger portions of the subduction zone depends largely DF and Eastern Margin Fault, EMF), with the west side up and running on the multiplicity and spatial distribution of evidence. parallel to the outer arc. The southward continuity of EMF to the History of great earthquakes in the Andaman–Sunda subduction zone Nicobar Islands is ambiguous. Further south, off Northern Sumatra, is poorly understood. Rajendran et al. (2006 and 2007) used historical and archeological data from the east coast of India, together with geologic evidence including paleoliquefaction features and subsided vegetation in the marshes on the east coast of Port Blair, to suggest that the pre-2004 event may have occurred around 1000 yr B.P. Ongoing paleotsunami investigations in the A&N Islands have indicated the possibility of anyounger event around 600 yr B.P. (Rajendran et al., 2008). Recent work by Jankaew et al. (2008) reports presence of sandsheets dating to about 14th to 15th Century A.D., based on paleotsunami evidence from the Phra Thong Island, on the coastal plains of Thailand. Obtaining chronological constraints of great earthquakes generated by the Andaman–Sunda subduction zone is an effort that is continuing; only with more data from the Indian Ocean littoral countries, the history of great events along this plate boundary can be better understood. The 2004 earthquake caused vertical displacements all along its rupture zone, with significant along-strike variations (Meltzner et al., 2006; Rajendran et al., 2007; Kayanne et al., 2007). During our post- earthquake surveys in the A&N region, we mapped many of these features and defined a pivot line separating the zones of uplift and subsidence (Fig. 2B and C). We also observed many geomorphological features, such as stepped coral terraces, that suggest episodes of past movements. Similarly, coseismic subsidence of coastal marshes in 2004 is potentially analogous to land-level changes that occurred in the past. We observed buried layers of peat in core sections at sites of some mangrove swamps that subsided in the 2004 earthquake, which we consider as evidence of past events (Rajendran et al., 2007). These features serve as proxies of tectonism and, if interpreted carefully, they can be used to reconstruct the regional tectonic history.
Load more

Recommended publications
  • BOBLME-2011-Ecology-07
    BOBLME-2011-Ecology-07 The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations (FAO) concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or products of manufacturers, whether or not these have been patented, does not imply that these have been endorsed or recommended by FAO in preference to others of a similar nature that are not mentioned. BOBLME contract: PSA-GCP 148/07/2010 For bibliographic purposes, please reference this publication as: BOBLME (2011) Country report on pollution – India. BOBLME-2011-Ecology-07 CONTENTS Chapter 1 The Bay of Bengal Coast of India 1 1.1 Biogeographical Features 1 1.2 Coastal Ecosystems of the Bay of Bengal Region 8 1.3 Coastal activities of high economic value in terms of GDP 19 Chapter 2 Overview of sources of pollution 33 2.1 Land based Pollution (Both point and non-point sources of 33 pollution) 2.2 Sea/ Marine-based Pollution 40 Chapter 3 Existing water and sediment quality objectives 43 and targets 3.1 Introduction 43 3.2 Wastewater generation in coastal areas 43 Chapter 4 The National Program Coastal Ocean Monitoring 49 and Prediction System 4.1 Mapping hotspots along the coast 49 4.2 Time series analysis and significant findings 53 4.3 Role of Ministries 67 4.3.1 Ministry of Environment and
    [Show full text]
  • Baratang Island
    travel BLEISURE The Andamans’ best kept secret Baratang Island The pristine Andaman and Nicobar Islands set a dreamy picture for travellers looking to get away from the city’s hubbub and the beaches here can give South Europe a run for its money. words // Edwina D'souza Andaman Map not to scale and Nicobar Islands Vistara | 22 | April 2019 travel BLEISURE he capital city of Port LAND OF THE JARAWAS any photographs and videos. It’s Blair is the gateway to the One can enter the Baratang an experience one captures with Andamans and its many Island via the Grand Trunk the eyes and not the lens, as you Tbeautiful islands like Road, Andamans’ only highway see the tribes coexist alongside Havelock, Ross and Neil Islands. connecting the south to the north. modern civilisation in present And one would be wrong to say It’s a three hour journey until you day world. that the Andamans is only about reach Jirkatang, which is the check the sun, sea and sands. Venture post to cross the Jarawa tribal A BOAT RIDE THROUGH CAVES inland and the Andamans surprises reserve. The Jarawas are one of The limestone caves in the you with its dense rainforests, the oldest existing human races Andamans are one of the most mangroves, creeks and some of in the world, who have shunned prominent attractions in the the rarest natural wonders unique interaction with the outside world. Baratang Island. Formed by the to this place. A fitting preview to According to estimates, only about compression of over millions of that is the Baratang Island in the 250 to 300 Jarawas remain and they years of gradual deposits of marine Middle Andamans, which is a still practice hunting and gathering life, corals and skeletons; these haven for nature lovers, birders as means of survival.
    [Show full text]
  • North Andaman (Diglipur) Earthquake of 14 September 2002
    Reconnaissance Report North Andaman (Diglipur) Earthquake of 14 September 2002 ATR Smith Island Ross Island Aerial Bay Jetty Diglipur Shibpur ATR Kalipur Keralapuran Kishorinagar Saddle Peak Nabagram Kalighat North Andaman Ramnagar Island Stewart ATR Island Sound Island Mayabunder Jetty Middle Austin Creek ATR Andaman Island Department of Civil Engineering Indian Institute of Technology Kanpur Kanpur 208016 Field Study Sponsored by: Department of Science and Technology, Government of India, New Delhi Printing of Report Supported by: United Nations Development Programme, New Delhi, India Dissemination of Report by: National Information Center of Earthquake Engineering, IIT Kanpur, India Copies of the report may be requested from: National Information Center for Earthquake Engineering Indian Institute of Technology Kanpur Kanpur 208016 www.nicee.org Email: [email protected] Fax: (0512) 259 7866 Cover design by: Jnananjan Panda R ECONNAISSANCE R EPORT NORTH ANDAMAN (DIGLIPUR) EARTHQUAKE OF 14 SEPTEMBER 2002 by Durgesh C. Rai C. V. R. Murty Department of Civil Engineering Indian Institute of Technology Kanpur Kanpur 208 016 Sponsored by Department of Science & Technology Government of India, New Delhi April 2003 ii ACKNOWLEDGEMENTS We are sincerely thankful to all individuals who assisted our reconnaissance survey tour and provided relevant information. It is rather difficult to name all, but a few notables are: Dr. R. Padmanabhan and Mr. V. Kandavelu of Andaman and Nicobar Administration; Mr. Narendra Kumar, Mr. S. Sundaramurthy, Mr. Bhagat Singh, Mr. D. Balaji, Mr. K. S. Subbaian, Mr. M. S. Ramamurthy, Mr. Jina Prakash, Mr. Sandeep Prasad and Mr. A. Anthony of Andaman Public Works Department; Mr. P. Radhakrishnan and Mr.
    [Show full text]
  • Chapter 2 Introduction to the Geography and Geomorphology Of
    Downloaded from http://mem.lyellcollection.org/ by guest on February 7, 2017 Chapter 2 Introduction to the geography and geomorphology of the Andaman–Nicobar Islands P. C. BANDOPADHYAY1* & A. CARTER2 1Department of Geology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata-700019, India 2Department of Earth & Planetary Sciences, Birkbeck, University of London, London, UK *Correspondence: [email protected] Abstract: The geography and the geomorphology of the Andaman–Nicobar accretionary ridge (islands) is extremely varied, recording a complex interaction between tectonics, climate, eustacy and surface uplift and weathering processes. This chapter outlines the principal geographical features of this diverse group of islands. Gold Open Access: This article is published under the terms of the CC-BY 3.0 license The Andaman–Nicobar archipelago is the emergent part of a administrative headquarters of the Nicobar Group. Other long ridge which extends from the Arakan–Yoma ranges of islands of importance are Katchal, Camorta, Nancowry, Till- western Myanmar (Burma) in the north to Sumatra in the angchong, Chowra, Little Nicobar and Great Nicobar. The lat- south. To the east the archipelago is flanked by the Andaman ter is the largest covering 1045 km2. Indira Point on the south Sea and to the west by the Bay of Bengal (Fig. 1.1). A coast of Great Nicobar Island, named after the honorable Prime c. 160 km wide submarine channel running parallel to the Minister Smt Indira Gandhi of India, lies 147 km from the 108 N latitude between Car Nicobar and Little Andaman northern tip of Sumatra and is India’s southernmost point.
    [Show full text]
  • Andaman Islands, India
    Journal of Global Change Data & Discovery. 2019, 3(4): 398-405 © 2019 GCdataPR DOI:10.3974/geodp.2019.04.15 Global Change Research Data Publishing & Repository www.geodoi.ac.cn Global Change Data Encyclopedia Andaman Islands, India Shen, Y.1 Liu, C.1* Shi, R. X.1 Chen, L. J.2 1. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; 2. National Geomatics Center of China, Beijing 100830, China Keywords: Andaman Islands; Andaman and Nicobar Islands; Bay of Bengal; Indian Ocean; India; data encyclopedia Andaman Islands is the main part of the An- daman and Nicobar Islands. It belongs to the Indian Union Territory of Andaman and Nicobar Islands, and its geo-location is 10°30′39″N–13°40′36″N, 92°11′55″E–94°16′ 38″E[1]. It is located between the Bay of Bengal and the Andaman Sea (Figure 1). It is separated from Coco Islands[2] by Coco Chanel at its north, and from Nicobar Islands[3] by Ten De- gree Chanel at its south. The Andaman Islands consists of Great Andaman Archipelago[4], Lit- tle Andaman Group[5], Ritchie’s Archipelago[6], [7] [8] East Volcano Islands and Sentinel Islands Figure 1 Map of Andaman Islands (Figure 2), with a total of 211 islands (islets, [1] (.kmz format) rocks) . The total area of the Andaman Islands is 5,787.79 km2, and the coastline is 2,878.77 km. Great Andaman Archipelago is the main part of Andaman Islands, and is the largest Ar- chipelago in Andaman Islands.
    [Show full text]
  • Andaman & Nicobar Islands Pondicherry. Census Atlas, Part-XII
    CENSUS OF INDIA 2001 SERIES-36 &35 PART-XII ANDAMANAND NICOBAR ISLANDS & PONDICHERRY CENSUS ATLAS Office of the Registrar General & Census Commissioner, India FOREWARD Census ofIndia, is perhaps, one of the largest castes and scheduled tribes, education and producer of maps in the country and in each census housing characteristics of the StatelUnion territory. decade nearly 10,000 maps of different categories The unit of the presentation of data is district/sub­ and themes are published. Earlier to 1961 Census, district. The adoption of GIS technique has not the maps were published in the census reports/tables only made this work more comprehensive but has as supporting documents. During Census 1961, a helped improve the quality of Census Atlas 200 I of new series of 'Census Atlas of States and Union State and Union territories. territories' was introduced which has been continued in the subsequent censuses. The maps have been prepared mostly by choropleth technique but other cartographic Census Atlas of States and Union territories methodologies, such as bar and sphere diagrams, 2001 are based on census data covering different pyramids, isotherms and isohyets have also been themes. Broadly, there are one hundred and adopted to prepare the maps as per the suitability twenty three themes proposed to be included in the and requirement of data. StatelUnion territory Census Atlas. But the number ns well its presentation varies from State to This project has been completed by the State depending upon the availability of data. The respective Directorates under the technical maps included in the publication are divided into supervision of Shri C.
    [Show full text]
  • Table 1. Place Names of the Andaman Islands Used by the Present Great Andamanese Tribe
    Table 1. Place names of the Andaman Islands used by the present Great Andamanese tribe Great Gloss Post-Colonial Names Andamanese Place Names Khringkosho A Pujjukar name Strait Island Phoco-toye A place where Phoco flower is Islet in front of the Strait found Island Siampsu A Pujjukar name An islet by the side of the Strait Island Jiro-tauro Place where Jiro tree is found An islet near Strait Island’s light house Kachawa A Pujjukar name An islet behind the Strait Island Ilumu-tauro The island of Onges (Little Little Andaman Andaman) Thi-lar-siro Land near the open sea, Island of Havelock island turtles Kokolot-barach A Pujjukar name An islet near Havelock Island’s jetty Bilikhu-tara- Cave of Bilikhu, the supernatural in Interview Island phong Great Andamanese Tebi-shiro Shores of the open sea Neil Island as well as for an Island near Mayabander Boa land Baratang Island Lurua The first fire/flame was found here Bluff Island Ret-phor Named after the two kinds of Mayabander bamboos Ret and Phor. Mauntenga Not known Land fall Island *Sorobul Dangerous area Jarawa areas (South Andaman) Marakele Present Great Andamanese still use Andaman archipelago this name Boing-taina Associated with the story of Maya An island of Jarawas near Lephai [whose wife eloped with Bluff Island, Northern part of No] the Jarawa reserve Mara-tong Place where Mar tree is found A place in Mayabander where Great Andamanese used to live (Now a helipad area) Gopta-pelang A Pujjukar name. Where animals Name for Chouldari in were killed and butchered.
    [Show full text]
  • District Statistical Handbook. 2010-11 Andaman & Nicobar.Pdf
    lR;eso t;rs v.Meku rFkk fudksckj }hilewg ANDAMAN AND NICOBAR ISLANDS Published by : Directorate of Economics & Statistics ftyk lkaf[;dh; iqfLrdk Andaman & Nicobar Administration DISTRICT STATISTICAL HAND BOOK Port Blair 2010-11 vkfFZkd ,oa lkaf[;dh funs'kky; v.Meku rFkk fudksckj iz'kklu iksVZ Cys;j DIRECTORATE OF ECONOMICS AND STATISTICS ANDAMAN AND NICOBAR ADMINISTRATION Printed by the Manager, Govt. Press, Port Blair PORT BLAIR çLrkouk PREFACE ftyk lkaf[;dh; iqfLrdk] 2010&2011 orZeku laLdj.k The present edition of District Statistical Hand Øe esa lksygok¡ gS A bl laLdj.k esa ftyk ds fofHkUu {ks=ksa ls Book, 2010-11 is the sixteenth in the series. It presents lacaf/kr egÙoiw.kZ lkaf[;dh; lwpukvksa dks ljy rjhds ls izLrqr important Statistical Information relating to the three Districts of Andaman & Nicobar Islands in a handy form. fd;k x;k gS A The Directorate acknowledges with gratitude the funs'kky; bl iqfLrdk ds fy, fofHkUu ljdkjh foHkkxksa@ co-operation extended by various Government dk;kZy;ksa rFkk vU; ,stsfUl;ksa }kjk miyC/k djk, x, Departments/Agencies in making available the statistical lkaf[;dh; vkWadM+ksa ds fy, muds izfr viuk vkHkkj izdV djrk data presented in this publication. gS A The publication is the result of hard work put in by Shri Martin Ekka, Shri M.P. Muthappa and Smti. D. ;g izdk'ku Jh ch- e¨gu] lkaf[;dh; vf/kdkjh ds Susaiammal, Senior Investigators, under the guidance of ekxZn'kZu rFkk fuxjkuh esa Jh ekfVZu ,Ddk] Jh ,e- ih- eqÉIik Shri B. Mohan, Statistical Officer.
    [Show full text]
  • Records of the Andaman Barn-Owl Tyto Deroepstorfii from North-, and Middle Andaman Islands S
    66 Indian BirDS VOL. 8 NO. 3 (PUBL. 22 APRIL 2013) species. The barbets are most probably breeding at Rishi Valley References now and seem they are here to stay. Ali, S., & Ripley, S. D., 1987. Compact handbook of the birds of India and Pakistan More on the Marshall’s Iora Aegithina nigrolutea: Since my together with those of Bangladesh, Nepal, Bhutan and Sri Lanka. 2nd ed. Delhi: first few sightings of Marshall’s Iora at Rishi Valley in January Oxford University Press. Pp. i–xlii, 1 l., 1–737, 52 ll. 2009 (Santharam 2010), I have been observing the birds at the Anderson, R. C., 2007. New records of birds from the Maldives. Forktail 23 (August): same locality fairly regularly. On 7 August 2011, I even noticed 135–144. the female carrying twigs in her beak, accompanied by the male Anderson, R. C., 2009. Do dragonfllies migrate across the western Indian Ocean?J. Trop. (which did not carry any twigs) flying to anAlbizzia sp., tree. Ecol. 25: 347–358. Anonymous. 1994. [Nehru Zoo Park]. Pitta 48: 2. More recently, on 21 November 2012, Suresh Jones and I Dewar, D., 1905. A list of the birds found in and about Madras. J. Bombay Nat. Hist. came across three Marshall’s Ioras calling and actively flying from Soc. 16 (3): 484–498. tree to tree at the Marippadu Reserve Forest, near Vayalpad to Grimmett, R., Inskipp, C., & Inskipp, T., 2011. Birds of the Indian Subcontinent. 2nd ed. the east of Madanapalle (Chittoor district, Andhra Pradesh). A London: Oxford University Press & Christopher Helm.
    [Show full text]
  • Echinodermata Associated with Coral Reefs of Andaman and Nicobar Islands
    Rec. zoo!. Surv. India: 100 (Part 3-4) : 21-60, 2002 ECHINODERMATA ASSOCIATED WITH CORAL REEFS OF ANDAMAN AND NICOBAR ISLANDS D. R. K. SASTRY Zoological Survey of India, A & N Regional Station, Port Blair - 744 102 INTRODUCTION Coral reefs are an important ecosystem of the coastal environment. The reef ecosystem IS highly productive and provides substratum, shelter, food etc. to a variety of biota. Consequently a number of faunal and floral elements are attracted towards the reef ecosystem and are closely associated with each other to form a community. Thus the reefs are also rich in biodiversity. Among the coral reef associates echinoderms are a conspicuous element on account of their size, abundance and effect on the reef ecosystem including the corals. In spite of their importance in the coral reef ecosystem and its conservation, very few studies were made on the echinoderm associates of the coral reefs. Though there were some studies elsewhere, the information on reef­ associated echinoderms of Indian coast is meager and scattered (see Anon, 1995). Hence an attempt is made here to collate the scattered accounts and unpublished information available with Zoological Survey of India. Since the information is from several originals and quoted references and many are to be cited often, these are avoided in the text and a comprehensive bibliography is appended which served as source material and also provides additional references of details and further information. ECHINODERMS OF CORAL REEFS More than 200 species of echinoderms occur in the reef ecosystem of Andaman and Nicobar Islands. These belong to five extant classes with 30 to 60 species of each class.
    [Show full text]
  • FAQ Welcome to Andamans. Your Convenience Is Our Prime Concern. Please Read Below to Get Answers to Your Most Frequent Queries A
    FAQ Welcome to Andamans. Your convenience is our prime concern. Please read below to get answers to your most frequent queries and prepare you trip to Andamans with these practical advices and tips. 1. Where Andaman Nicobar Islands Locates? The Andaman and Nicobar Islands, located in the south-east of the Indian mainland geographically, float in splendid isolation in the Bay of Bengal. Once a hill range extending from Myanmar to Indonesia, these picturesque undulating islands, islets numbering around 836, are covered with dense rain-fed, damp and evergreen forests and endless varieties of exotic flora and fauna. 2. How to find Andaman on map? Coordinates: 11.7401° N, 92.6586° E 3. How to Reach Andaman? By Air and Ship The Veer Savarkar Airport, an International Airport is located in the capital town of Port Blair, the gateway to Andaman and Nicobar Islands. Port Blair, is connected with Chennai, Kolkata, New Delhi and Bangalore by air. Air India, Go Air, Indigo, Vistara & Spice Jet Airlines operate regular flights. Foreign chartered flights are also permitted to land at Port Blair subject to the fulfilment of guidelines of the Directorate General of Civil Aviation. Regular passenger ship services are available to Port Blair from Chennai, Kolkata and Visakhapatnam and back. There are three to four sailings every month from Kolkata and Chennai to Port Blair and vice-versa. There is only one sailing for Visakhapatnam in a month. The voyage takes about 50 to 60 hours during fair weather. 4. Is the passport required for Andaman? No, Indian citizens do not require a passport to visit Andaman.
    [Show full text]
  • The Jarawa and Their Society
    Chapter - 3 The Jarawa and Their Society 3.1. The term Jarawa in common parlance was synonymous with hostility and nudity in pre-1997 days. In the Aka-bea Andamanese language the word ‘Jarawa’ means “stranger”. But the Jarawas call themselves as “Ang” while the non- tribals are termed as “eenem” by Jarawas. The Jarawa language is yet to be studied in depth. However, preliminary studies indicate that the sound system of the Jarawa language attests 13 vowel phonemes and 26 consonant phonemes. The word system of the language attests six words classes namely noun, pronoun, verb, adjective, adverb and particle (Raja Singh 2002:116-119). The Jarawas are characterized by the physical features of short stature, dark skin, frizzly and wooly hair, broad to round head shape. 3.2. The Jarawa tribe inhabits today the Western region of South Andaman and Middle Andaman Islands. It has three socially discernable territorial divisions viz. Northern Group occupying Western part of Middle Andaman Island, Southern Group and Central Group occupying Western part of South Andaman Island. The Northern Group is known among the Jarawas as Tanmad and as ‘Kadamtala Jarawa’ among non-tribals. Southern Group is known as Boiab among Jarawas and non- Jarawas call them as ‘Tirur Jarawas’. The Central Group is known as Thidong among the Jarawa and among non-Jarawas it is known as ‘R. K. Nallah Jarawas’. Demography 3.3. The multi-disciplinary Research teams enumerated 266 Jarawas altogether. 84 in Southern Group (Boiab), 78 in Central Group (Thidong) and 104 in Northern Group (Tanmad). The Age - sex distribution among the Jarawas is indicated in Table 3.1.
    [Show full text]