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Iceland Can Be Considered Volcanologist “Heaven”
Iceland can be considered volcanologist “heaven” 1) Sub-aerial continuation of the Mid-Atlantic Ridge 2) Intersection of a mantle plume with a spreading ocean ridge 3) Volcanism associated with tectonic rifting 4) Sub-glacial volcanism 5) Tertiary flood (plateau) basalts 6) Bi-modal volcanism 7) Submarine volcanism 8) 18 historically active volcanoes 9) Eruptions roughly every 5 years 1. The North Atlantic opened about 54 Ma separating Greenland from Europe. 2. Spreading was initially along the now extinct Agir ridge (AER). 3. The Icelandic plume was under Greenland at that time. 4. The Greenland – Faeroe ridge represents the plume track during the history of the NE Atlantic. Kolbeinsey ridge (KR) 5. During the last 20 Ma the Reykjanes Ridge (RR) Icelandic rift zones have migrated eastward, stepwise, maintaining their position near the plume 6. The plume center is thought to be beneath Vatnajökull 1 North Rift Zone – currently active East Rift Zone – currently active West Rift Zone – last erupted about 1000-1300 AD [Also eastern (Oræfajökull) and western (Snæfellsnese) flank zones] Rift zones comprise en-echelon basaltic fissure swarms 5-15 km wide and up to 200 km long. Over time these fissures swarms develop a volcanic center, eventually maturing into a central volcano with a caldera and silicic Tertiary volcanics > 3.1 Ma volcanism Late Tertiary to Early Quaternary 3.1 – 0.7 Ma Neo-volcanic zone <0.7 - present Schematic representation of Iceland’s mantle plume. The crust is about 35 – 40 km thick Iceland’s mantle plume has been tomographically imaged down to 400 km. Some claim even deeper, through the transition zone, and down to the core – mantle boundary. -
1 the Influence of Groyne Fields and Other Hard Defences on the Shoreline Configuration
1 The Influence of Groyne Fields and Other Hard Defences on the Shoreline Configuration 2 of Soft Cliff Coastlines 3 4 Sally Brown1*, Max Barton1, Robert J Nicholls1 5 6 1. Faculty of Engineering and the Environment, University of Southampton, 7 University Road, Highfield, Southampton, UK. S017 1BJ. 8 9 * Sally Brown ([email protected], Telephone: +44(0)2380 594796). 10 11 Abstract: Building defences, such as groynes, on eroding soft cliff coastlines alters the 12 sediment budget, changing the shoreline configuration adjacent to defences. On the 13 down-drift side, the coastline is set-back. This is often believed to be caused by increased 14 erosion via the ‘terminal groyne effect’, resulting in rapid land loss. This paper examines 15 whether the terminal groyne effect always occurs down-drift post defence construction 16 (i.e. whether or not the retreat rate increases down-drift) through case study analysis. 17 18 Nine cases were analysed at Holderness and Christchurch Bay, England. Seven out of 19 nine sites experienced an increase in down-drift retreat rates. For the two remaining sites, 20 retreat rates remained constant after construction, probably as a sediment deficit already 21 existed prior to construction or as sediment movement was restricted further down-drift. 22 For these two sites, a set-back still evolved, leading to the erroneous perception that a 23 terminal groyne effect had developed. Additionally, seven of the nine sites developed a 24 set back up-drift of the initial groyne, leading to the defended sections of coast acting as 1 25 a hard headland, inhabiting long-shore drift. -
Baja California Sur, Mexico)
Journal of Marine Science and Engineering Article Geomorphology of a Holocene Hurricane Deposit Eroded from Rhyolite Sea Cliffs on Ensenada Almeja (Baja California Sur, Mexico) Markes E. Johnson 1,* , Rigoberto Guardado-France 2, Erlend M. Johnson 3 and Jorge Ledesma-Vázquez 2 1 Geosciences Department, Williams College, Williamstown, MA 01267, USA 2 Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada 22800, Baja California, Mexico; [email protected] (R.G.-F.); [email protected] (J.L.-V.) 3 Anthropology Department, Tulane University, New Orleans, LA 70018, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-413-597-2329 Received: 22 May 2019; Accepted: 20 June 2019; Published: 22 June 2019 Abstract: This work advances research on the role of hurricanes in degrading the rocky coastline within Mexico’s Gulf of California, most commonly formed by widespread igneous rocks. Under evaluation is a distinct coastal boulder bed (CBB) derived from banded rhyolite with boulders arrayed in a partial-ring configuration against one side of the headland on Ensenada Almeja (Clam Bay) north of Loreto. Preconditions related to the thickness of rhyolite flows and vertical fissures that intersect the flows at right angles along with the specific gravity of banded rhyolite delimit the size, shape and weight of boulders in the Almeja CBB. Mathematical formulae are applied to calculate the wave height generated by storm surge impacting the headland. The average weight of the 25 largest boulders from a transect nearest the bedrock source amounts to 1200 kg but only 30% of the sample is estimated to exceed a full metric ton in weight. -
The Surtsey 1963 Eruption Plume, Characteristics and Tephra Dispersal
Geophysical Research Abstracts Vol. 21, EGU2019-17144, 2019 EGU General Assembly 2019 © Author(s) 2019. CC Attribution 4.0 license. The Surtsey 1963 eruption plume, characteristics and tephra dispersal Einar Sindri Ólafsson (1), Magnus T Guðmundsson (2), and Esther R. Guðmundsdóttir (3) (1) Institute of Earth Sciences, University of Iceland, Reykjavik, Iceland ([email protected]), (2) Institute of Earth Sciences, University of Iceland, Reykjavik, Iceland ([email protected]), (3) Institute of Earth Sciences, University of Iceland, Reykjavik, Iceland ([email protected]) Surtsey is a basaltic island in the south-western end of Vestmannaeyjar archipelago off the south coast of Iceland and is a part of the Vestmannaeyjar volcanic system. It is built from the ocean floor at about 130 m depth in a series of eruptions during 1963-1967, one of the longest eruption in Iceland in historical times. The eruptions can be split into four phases. The first phase of the eruptions was explosive and phreatomagmatic in character. The aim of this study is to put constraints on the mass of tephra transported with the plume. This is done in two ways: (1) Study soil profiles on Heimaey and on the mainland to look for tephra deposits from Surtsey as well as note contemporary descriptions of tephra fallout; and (2) by compiling existing contemporary records of plume height and use plume height – mass transport systematics to estimate the transport. Finally, we compare the outcomes of (1) and (2). Eruption started on 14 November 1963. It was explosive and fed an eruption plume rising typically to 5-9 km in November and December 1963. -
Phoca Vitulina) in Icelandic Waters
Monitoring trends in the abundance of harbour seals (Phoca vitulina) in Icelandic waters Erlingur Hauksson Fornistekkur 14, IS-109 Reykjavik, Iceland ABSTRACT Harbours seal ( Phoca vitulina) numbers along the coast of Iceland were monitored by aerial survey in the period 1980-2006. Trends in the abundance of the harbour seal population on the whole coast and in coastal regions of Iceland waters were estimated using ANCOVA on the sur - vey counts, corrected for the influence of several covariates. Harbour seals were found in every coastal area, but were most abundant in Faxaflói, Breiðafjörður and on the northwest coast in the beginning of this study. Harbour seal numbers declined significantly at a rate of res t = -0.04 (SE 0.005) y r-1 during this period. Decline was highest in Faxaflói and at the south coast ( ≅7%), while the east coast experienced a significant but lesser ( ≅1%) decline. Other coastal areas did not show significant trends. The northwest coast was the richest harbour seal area in Iceland in 2006. In Icelandic waters seals are commercially harvested, and unreported but probably high numbers of harbour seals are killed intentionally by shooting and accidentally in fishing gear each year. These factors likely contributed to the overall observed decline in seal numbers. Hauksson, E. 2010. Monitoring trends in the abundance of harbour seals ( Phoca vitulina ) in Icelandic waters. NAMMCO Sci. Publ. 8:227-244. INTRODUCTION ecosystem dynamics, its potential interactions with fisheries, the impacts of global climate An understanding of population status of the change, and other anthropogenic changes Icelandic harbour seal ( Phoca vitulina vituli - caused in habitat (Small et al. -
Subglacial and Submarine Volcanism in Iceland
Mars Polar Science 2000 4078.pdf SUBGLACIAL AND SUBMARINE VOLCANISM IN ICELAND. S. P. Jakobsson, Icelandic Inst. of Natural His- tory, P. O. Box 5320, 125 Reykjavik, Iceland Introduction: Iceland is the largest landmass ex- mounds, ridges and tuyas [5]. The thickness of basal posed along the Mid-Ocean Ridge System. It has been basaltic pillow lava piles often exceeds 60-80 meters constructed over the past 16 Ma by basaltic to silicic and a 300 m thick section has been reported. Pillow volcanic activity occurring at the Mid-Atlantic Ridge, lavas may also form lenses or pods at a higher level in and is topographically elevated because of the abundant the volcanoes. igneous material produced in association with the Ice- It has been suggested that at a water depth less than land hot spot, the center of which is thought to be lo- approximately 100-150 m, basaltic phreatic explosions cated beneath Vatnajokull glacier [1]. The axial rift produce hydroclastites. It appears feasible to subdivide zones which run through Iceland from southwest to the hyaloclastites of the Icelandic ridges and tuyas, ge- northeast are in direct continuation of the crestal zones netically into two main types. A substantial part of the of the Mid Atlantic Ridge and are among the most ac- base of the submarine Surtsey tuya is poorly bedded, tive volcanic zones on Earth. unsorted, hydroclastite, which probably was quenched Subglacial Volcanism: Volcanic accumulations of and rapidly accumulated below the seawater level with- hyaloclastites which are deposits formed by the intru- out penetrating the surface [6]. Only 1-2 % of the vol- sion of lava beneath water or ice and the consequent ume of extruded material in the 1996 Gjalp eruption fell shattering into small angular vitric particles, combined as air-fall tephra, the bulk piled up below the ice [4]. -
Flugtalningar 2011 Endanleg
VMST/11051 Landselstalning úr lofti árið 2011: Framvinda og niðurstöður Sandra M. Granquist, Erlingur Hauksson, Arna Björg Árnadóttir og Jacob Kasper Nóvember 2011 Veiðimálastofnun Veiðinýting • Lífríki í ám og vötnum • Rannsóknir • Ráðgjöf VMST/11051 Landselstalning úr lofti árið 2011: Framvinda og niðurstöður Sandra M. Granquist 1, Erlingur Hauksson 2, Arna Björg Árnadóttir 1 og Jacob Kasper 3,4 1 2 Unnið í samstarfi við Selasetur Íslands , Rannsjá , 3 4 BioPol ehf . og Hafrannsóknarstofnun 1. Selasetur Íslands , Brekkugata 2, 530 Hvammstanga, 2. Rannsjá , Fornistekkur 14, 109 Reykjavík, 3. Biopol ehf . Einbúastíg 2, 545 Skagaströnd, 4. Hafrannsóknarstofnun , Einbúastíg 2, 545 Skagaströnd Veiðimálastofnun Veiðinýting • Lífríki í ám og vötnum • Rannsóknir • Ráðgjöf Efnisyfirlit Efnisyfirlit .................................................................................................................................................. i Töfluskrá ...................................................................................................................................................ii Myndaskrá ................................................................................................................................................ii Viðaukaskrá ..............................................................................................................................................ii Ágrip ....................................................................................................................................................... -
Functional Design of Coastal Structures
FUNCTIONALFUNCTIONAL DESIGNDESIGN OFOF David R. Basco, Ph.D, P.E. Director, The Coastal Engineering Center Old Dominion University,Norfolk, Virginia USA 23529 [email protected] DESIGNDESIGN OFOF COASTALCOASTAL STRUCTURESSTRUCTURES •• FunctionFunction ofof structurestructure •• StructuralStructural integrityintegrity •• PhysicalPhysical environmentenvironment •• ConstructionConstruction methodsmethods •• OperationOperation andand maintenancemaintenance OUTLINEOUTLINE •• PlanPlan formform layoutlayout - headland breakwaters - nearshore breakwaters - groin fields • WaveWave runuprunup andand overtopping*overtopping* - breakwaters and revetments (seawalls, beaches not covered here) •• WaveWave reflectionsreflections (materials(materials includedincluded inin notes)notes) * materials from ASCE, Coastal Engineering Short Course, CEM Preview, April 2001 SHORESHORE PARALLELPARALLEL BREAKWATERS:BREAKWATERS: HEADLANDHEADLAND TYPETYPE Design Rules, Hardaway et al. 1991 • Use sand fill to create tombolo for constriction from land • Set berm elevation so tombolo always present at high tide • Set Yg/Lg =• 1.65 for stable shaped beach • Set Ls/Lg = 1 • Always combine with new beach fill • See CEM 2001 V-3 for details KEYKEY VARIABLESVARIABLES FORFOR NEARSHORENEARSHORE BREAKWATERBREAKWATER DESIGNDESIGN Dally and Pope, 1986 Definitions: Y = breakwater distance from nourished shoreline Ls = length of breakwater Lg = gap distance d = water depth at breakwater (MWL) ds = water depth• at breakwater (MWL) •Tombolo formation: Ls/Y = 1.5 to 2 single = 1.5 system •Salient formation: Ls/ = 0.5 to 0.67 = 0.125 long systems (a) (b) Process Parameter Description 1. Bypassing Dg/Hb Depth at groin tip/breaking wave height 2. Permeability • Over-passing Zg (y) Groin elevation across profile, tidal range • Through-passing P(y) Grain permeability across shore • Shore-passing Zb/R Berm elevation/runup elevation 3. Longshore transport Qn/Qg Net rate/gross rate Property Comment 1. Wave angle and wave height Accepted. -
Hafrannsóknastofnunin. Fjölrit Nr. 133
Hafrannsóknastofnunin. Fjölrit nr. 133 Friðun svæða og skyndilokanir á Íslandsmiðum Sögulegt yfirlit Sigfús A. Schopka Reykjavík 2007 2 Hafrannsóknastofnunin. Fjölrit nr. 133 Friðun svæða og skyndilokanir 3 EFNISYFIRLIT FORMÁLI………………………………………………………………………………….....5 ÁGRIP……………………………………………………………………………………........7 ABSTRACT…………………………………………………………………………………...7 1. INNGANGUR……………………………………………………………………………...9 2. FYRSTU SKREFIN………………………………………………………………………..9 2.1 Friðun hrygningarstöðva síldar 1969 og1970…………………………………….............11 3. FRIÐUN SVÆÐA 1972-1976.............................................................................................12 3.1 Norðausturhólfið.................................................................................................................13 3.2 Frímerkið.............................................................................................................................13 3.3 Tillögur Hafrannsóknastofnunarinnar um nýtingu íslenskra fiskstofna............................. 14 3.4 Gildran................................................................................................................................15 3.5 Strandagrunn.......................................................................................................................15 3.6 Kolbeinsey..........................................................................................................................16 3.7 Reykjafjarðaráll...................................................................................................................16 -
Along the Seashore
Along the seashore 8ljkiXc`X`jk_\nfic[Ëjj`ok_cXi^\jk ZflekipXe[`jjliifle[\[Ypj\X% @k_XjXmXjkZfXjkc`e\Çjfd\*.''' b`cfd\ki\j%8cfe^`kXi\dfi\k_Xe((''' Y\XZ_\jXe[XeldY\if]jklee`e^ eXkliXc]\Xkli\j#jlZ_XjM`Zkfi`XËjKn\cm\ 8gfjkc\jXe[N\jk\ie8ljkiXc`XËj E`e^XcffI\\]%Knffk_\ij#k_\>i\Xk 9Xii`\iI\\]Xe[=iXj\i@jcXe[#Xi\ Nfic[?\i`kX^\8i\Xj% Dfjkf]8ljkiXc`XËjgfglcXk`fec`m\j Zcfj\kfk_\ZfXjkc`e\#gXik`ZlcXicp`ek_\ \XjkXe[jflk_$\Xjk%Fecp(,g\iZ\ekc`m\j dfi\k_XeXe_fliËj[i`m\]ifdk_\j\X% K_\mXip`e^Zc`dXk`ZZfe[`k`fejXe[ \em`ifed\ekjf]8ljkiXc`XËjZfXjkc`e\Xccfn `kkfjlggfikXi`Z_[`m\ij`kpf]jg\Z`\j% @edfi\i\Z\ek[\ZX[\j#jfd\f]k_\j\# Xe[jfd\]iX^`c\ZfXjkXc\em`ifed\ekj# _Xm\Y\\e`eZi\Xj`e^cpk_i\Xk\e\[Yp gfcclk`fe#liYXe[\m\cfgd\ekXe[ kfli`jd% ( 9iX`ejkfidknfZcXjjc`jkj1 X eXkliXcZfXjkXc]\Xkli\jXe[ Y _ldXeXZk`m`k`\jfi[\m\cfgd\ekj kpg`ZXccp]fle[Xcfe^ZfXjkc`e\j% ) K_\cXi^\`dX^\fek_\c\]k`jXj\Zk`fe f]k_\Kn\cm\8gfjkc\j% X N_p[fpflk_`ebk_`jd`^_kY\ • How coastlines are formed jlZ_XgfglcXikfli`jkXkkiXZk`fe6 • In what ways people use coastal environments Y ?fnZflc[kfli`jdgfk\ek`Xccp and some of the effects of this use X]]\Zkk_`jeXkliXc\em`ifed\ek6 • Why pollution is causing serious problems for many * N_Xkjfikjf]gi\jjli\j[fpflk_`eb Australian coastlines _ldXeXZk`m`kpXe[[\m\cfgd\ek • How coastlines can be managed to balance competing d`^_kY\gcXZ`e^fek_\jki\kZ_f] demands in a sustainable way ZfXjkc`e\`ek_\jdXcc\i`dX^\6<ogcX`e% 9eWijWbbWdZ\ehci BOUT 85 PER CENT of Australia’s population lives in coastal towns and cities (more A than 25 per cent within three kilometres of the coast). -
Skrá Yfir Íslensk Skip Og Báta 2018
Skrá yfir íslensk skip og báta 2018 Skráð þilfarsskip og opnir bátar samkvæmt aðalskipaskrá þann 1. janúar 2018 Register of Icelandic Decked Ships and Open Boats on January 1st 2018 Jákvæðni Fagmennska Traust Virðing - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Samgöngustofa Ármúla 2 108 Reykjavík http://www.samgongustofa.is/ Vefútgáfa 2018. Heimilt er að prenta vefritið til eigin nota en óheimilt er að prenta það eða afrita með nokkrum öðrum hætti í því skyni að selja það án heimildar frá Samgöngustofu. Efnisyfirlit Contents Íslensk skip og bátar — yfirlit 1. janúar 2018 1 Summary of Icelandic Decked Ships and Open Boats on January 1st 2018 Nýskráningar og endurskráningar 2017 2 Registered Ships and Boats in 2017 Afskráningar 2017 3 Decommissioned Ships and Boats in 2017 Skýringar við skipaskrá 4 Key to the Register of Ships Skýringar við bátaskrá 7 Key to the Register of Boats Skráð þilfarsskip samkvæmt aðalskipaskrá 1. janúar 2018 8 Register of Icelandic Decked Ships on January 1st 2018 Skrá yfir opna báta 1. janúar 2018 115 Register of Icelandic Open Boats on January 1st 2018 Einkaréttur á skipsnöfnum 244 Prerogative of Icelandic Ship Names Íslensk skip og bátar — yfirlit 1. janúar 2018 Á aðalskipaskrá 1. janúar 2018 voru samtals 2.295 skip. Skipum á íslenskri aðalskipaskrá hefur fjölgað um 6 frá árinu 2017. Á árinu 2016 voru frumskráð og endurskráð skip 36, afskráð skip voru 36. Hér gefur að líta töflu yfir þróun skipastólsins 1. janúar ár hvert. Fjöldi og stærð 2011 2012 2013 2014 2015 2016 2017 2018 Þilfarsskip 1.051 1.050 1.060 1.056 1.051 1.041 1.031 1.032 Brúttótonn 203.319 206.248 212.155 198.871 194.278 198.079 200.246 208.375 Opnir bátar 1.199 1.216 1.238 1.244 1.245 1.243 1.258 1.263 Brúttótonn 7.112 7.233 7.460 7.538 7.591 7.621 8.935 7.327 Heildarfjöldi 2.250 2.266 2.298 2.300 2.296 2.284 2.289 2.295 Heildarbrúttótonn 210.431 213.481 219.615 206.409 201.869 205.701 209.181 215.702 Skip á aðalskipaskrá skiptast þannig eftir skráður notkunarflokkum: 1.jan.16 1.jan.17 1. -
In in Iceland: Pltihpopulationpg Changees and Ditht Main Threats
Atlantic Puff in in Iceland: PltihPopulationpg changees and ditht main threats Aevarea Petersen eese1 &Th& Thhorkello e LL. Thorarinsson o a sso 2 1Icelandic Institute of Natural Historry 2North East Iceland Nature Center 1. The Icelandic populationpp 3. Population chaanges The Atlantic Puffin Fratercula arctica is Prior to 2000 mean increase of 4.3%/yr believed to be the most common wasas recordedeco ded at tenten colonies,co o es, includingcud g bdibreedingg bibird d speciesp i iin IldIceland. MtMost the largest ones studied (>30000 pairs). recent estimate is 3-4 million pairspairs, or The greatest increease was 15%/yr/yr, about half the world population. The whichc iss exceptioneceptonala andadffoundou d in a populationpplti iis ditibtddistributed mostlytly on colony established in 1975 (Petersen islandsislands, among roughly 800 coloniescolonies, the 2010). largest about 200 thousand pairs. Many off ththe coloniesli are veryy small,ll onlyly a ffew More recently eightt colonies showed a pairs. Some islands only have single mean decline of 4.9%/yr. Same has pairs. takenta e placepace ono thetee Westmanest a Islandssa ds the largest Puffin coolony aggregation in 22. Data Availability the world (Hansenn 2009, Hansen & Although other ffactors may also affectff We reviewed available unpublished and GGardarssonGa da sso 2009009). individual Puffin coloniescolonies, climate ppublished blished information on poppopulationpp lation change and resulting effects on the changes. Colony sizes were estimated No quantitative datta are available for ffood resources is currently the greatest mainly from occupied burrow counts. mostost Icelandicce a d c Puffinuff n coloniesco o es. potential threat to Icelandic Puffins. PopPopulationp lation dedevelopment, elopmentp rangingggfrom 5 to 33 yearsyears, is reviewed for 19 colonies 4.