Western Tip Research Articles

Nusantara: Delineating Its Authentic Map Based on Indigenous Sources

To date, there is yet a map of Nusantara and the understanding of its geographical area is based on logical assumption that it is a combination of ‘nusa’ (nation) and ‘tara’ (between) which is not so. This paper is an effort to subdue its absence by delineating its the map in a diagrammatic presentation based on indigenous sources which directly related to it, NAgara-KA›rtAgama (the 14th century Javanese Majapahit court chronicle) and supported by other indigenous sources, namely, Pararaton (14century) and the Malay Annals (Sejarah Melayu) (17th century). Based on these indigenous sources, affirm that Nusantara is an indigenous geopolitical region which covers a vast area of southeastern part of present Asian region with its northern tip starts from the Isthmus of Kra (southern Thailand) and stretches down to its southern tip at Western Papua New Guinea; and its western tip starts from west Sumatera (Barus) and stretches eastward to its eastern tip at Manila (Saludung/Salurong). The objective of this paper is to reify the map of Nusantara so that it could easily visualized by everybody with all level of knowledge.

A new Holocene relative sea-level curve for western Brittany (France): Insights on isostatic dynamics along the Atlantic coasts of north-western Europe

This study presents new Relative Sea Level (RSL) data that were obtained in the Finistère region (Western tip of Brittany, France) and the implications those data have for the understanding of the isostatic dynamics across north-western Europe, and more specifically along the Atlantic and Channel coasts. New stratigraphic sequences were obtained and analyzed to derive 24 new Sea-level Index Points, in which 6 are basal. These new data considerably increase the knowledge we have of the RSL evolution along the coasts of Western Brittany since the last 8 kyr B.P. From this new dataset, RSL was estimated to rise continuously over the last 8 kyr with a major inflection at ca. 6 kyr cal. BP. Our results show large vertical discrepancies between the RSL records of Brittany and South-Western UK, with the latter plotting several meters below the new data. From this comparison we suggest that the two regions underwent a very different pattern and/or amplitude of subsidence during the last 8 kyr which has implications for the spatial and temporal pattern of the peripheral bulge of the European ice sheets. We compared our data against predictions from Glacio-Isostatic Adjustment models (GIA models). There are large misfits between RSL observations and the predictions of the global (ICE-5G (VM2a) – Peltier, 2004, GLAC1-b – Tarasov and Peltier, 2002; Tarasov et al., 2012, Briggs et al., 2014) and regional UK models (“BIIS” – Bradley et al., 2009; Bradley et al., 2011; “Kuchar”- Kuchar et al., 2012), which can't be resolved through significant changes to the deglaciation history and size of the British–Irish Ice sheet. Paleo-tidal modelling corrections indicate regional changes in the tidal ranges played a negligible role in the data-model misfits. Hence, we propose that the misfits are due to some combination of: (i) unaccounted mass-loss of far-field ice-sheets (Antarctic ice-Sheet or Laurentide Ice-Sheet), (ii) unresolved differences in the deglaciation history and size of the Fennoscandian Ice sheet or, more likely, (iii) significant lateral variations in the Earth's structure across the English Channel.

Two new species of the genus Cophixalus from the Raja Ampat Islands west of New Guinea (Amphibia, Anura, Microhylidae)

Based on morphological and bioacoustic traits, two new species of the microhylid genus Cophixalus Boettger, 1892 are described from the Raja Ampat Islands off the western tip of New Guinea. Both are small (SUL < 23 mm), slender, scansorial species that are morphologically most similar to Cophixalus tetzlaffi Günther and C. monosyllabus Günther, two congeners also known only from far western New Guinea. Their description brings the total number of Cophixalus known from New Guinea and surrounding islands to 46, and the total number from western New Guinea (Papua and West Papua Provinces including the Raja Ampat Islands) to 10. One Cophixalus specimen from Salawati Island is considered a hermaphrodite because it has a well-developed vocal sac and vocal slits, but also has an ovary containing eggs in an advanced developmental stage. This frog uttered advertisement calls that did not differ from calls of conspecific males. The first evidence of the genus Cophixalus from Misool Island is also documented.

Patterns of Quaternary uplift of the Corinth rift southern border (N Peloponnese, Greece) revealed by fluvial landscape morphometry

The Rift of Corinth is a world-class example of young active rifting and, as such, is an ideal natural laboratory of continental extension. However, though much investigated for two decades, several aspects of the mechanisms at work are still poorly understood. The aim of this paper is a detailed morphometric study of the fluvial landscape response to the tectonic uplift of the rift southern shoulder in order to reconstruct the rift's Quaternary evolution, with special attention to timing, location, and intensity of uplift episodes. Based on the use of a large set of catchment and long profile metrics complemented by the new R/SR integrative approach of the regional drainage network, we identified three distinct episodes of uplift of the northern Peloponnese coastal tract, of which the intermediate one, dated around 0.35–0.4Ma, is only recorded in the topography of the central part of the rift shoulder, and the youngest one appears to have propagated from east to west over the last 10–20ka. While net uplift remained minimum in the eastern part of the study area during the whole Quaternary, it shows a clear maximum in the central part of the rift shoulder since 0.4Ma and an eastward shift of this maximum in recent times. Maximum uplift rates calculated from the morphometric data are of >1.05 and 2–5mmyear−1 for, the mid-Middle Pleistocene and Holocene uplift episodes, respectively. The morphometric evidence reveals an onshore uplift history remarkably consistent with the rift evolution reconstructed from other data sets. In the long term, it shows a stable pattern of maximum activity in the central part of the rift, confirming previous conclusions about the absence of rift propagation. In the short term, it sheds light on a possible E–W migration of the zone of recent uplift, suggesting that in the near future fault activity and seismic hazard might concentrate in the Heliki–Aegion area, at the western tip of this uplift wave.

Complex fault-fold interactions during the growth of the Jabal Qusaybah anticline at the western tip of the Salakh Arch, Oman

The Jabal Qusaybah anticline is located at the western end of the Salakh Arch, a major salient in the foothills of the Oman Mountains. We performed a structural and petrographical-geochemical study of vein sets and fault zones associated with the development of this anticline. Our data illustrate a complex deformation pattern both in space and time, characterized by the unusual presence of widespread NE-SW left-lateral strike-slip fault zones trending oblique to the E-W fold axial strike, and of abundant and well-developed N-S fold-perpendicular extensional fault zones associated with axial bulging and dilation, well developed in the central region of the anticlinal crest. We propose a three-stage evolution for the Jabal Qusaybah anticline, starting with prefolding jointing in the foreland of the late Cretaceous Oman Mountains, and followed by development of extensional faulting in Campanian times. Positive inversion of the Qusaybah Fault, possibly in Miocene times, caused development of a layer-parallel shortening fabric and amplification the Jabal Qusaybah Anticline, in concomitance with the activity of NE-SW left-lateral strike-slip fault zones that triggered N-S, fold-perpendicular extensional faulting, particularly in the axial bump of the anticline. The final evolutionary stage was characterized by further amplification of the axial bump and related N-S extensional fracturing and by uplift and exhumation. To explain the complex noncylindrical fault-fold interactions in the study anticline, we tentatively propose that they were triggered by near foredeep-parallel tapering of the sedimentary/tectonic overburden of the Ara evaporites.

Present-day surface deformation and tectonic insights of the extensional Ilan Plain, NE Taiwan

Taiwan’s mountain belt is an ideal location to address major questions regarding mechanisms of lithospheric deformation in convergent settings, mountain building processes from oceanic subduction to continental subduction, and post orogenic extension. In the northeast of this belt, the Ilan Plain is a triangular, deltaic plain characterized by a flat topography close to the sea level, and surrounded by the high mountains of the Hsuehshan Range to the northwest, and the Central Range to the southeast. Its eastern coast faces the western tip of the Okinawa Trough, the back-arc basin of the Ryukyu subduction zone. In this study, we analyzed the present-day surface deformation of the Ilan Plain, aiming at deciphering its relationships with basement faults and the regional geodynamic setting. Our approach is mainly based on surface vertical displacements revealed by Persistent Scatterer Interferometry Synthetic Aperture Radar (PSI), which indicate that there is an area of active subsidence (∼18mm/yr) located in the southern part of the plain in probable connection with active basement faults and in agreement with previous geodetic measurements and existing geophysical data. Our PSI results also suggest that the subsidence occurring in the Ilan Plain has moved from north to south during Quaternary in relation with extrusion of the belt due to the westward propagation of the Okinawa Trough through the Taiwan Mountains.

Active faulting at the western tip of the Gulf of Corinth, Greece, from high-resolution seismic data

Abstract The Gulf of Corinth is one of the fastest-spreading intra-continental rifts on Earth. GPS data indicate that the rift is currently opening in a NNE-SSW direction, with a rate of extension reaching up to 16 mm yr− 1 in its westernmost part. Although the rest of the offshore rift has been well studied, the western tip of the rift is still poorly explored. We present an accurate map of submarine faults in this area based on two high-resolution seismic reflection surveys (single-channel sparker). In the eastern part of the studied area, the sedimentary infill is affected by the known North Eratini, South Eratini, and West Channel faults. Further to the west, the seafloor is mostly flat and is bounded to the north by the normal, south-dipping, Trizonia fault. To the north, the shallower part of the Gulf shows to the east a diffuse pattern of normal and strike-slip deformation, which is replaced to the west by a 7.5 km long SE striking strike-slip fault zone, called the Managouli fault zone. To the westernmost tip of the Gulf, in the Nafpaktos Basin, two fault sets with different strikes are encountered; the one with a NE-SW strike exhibits a clear strike-slip component. The western tip of the Gulf of Corinth is the only part of the Corinth Rift where convincing evidence for strike-slip movement has been found. This fault pattern is likely related to the complex deformation occurring at the diffuse junction at the western tip of the Rift between three crustal blocks: Continental Greece, Peloponnese, and the Ionian Island-Akarnania block.

서·남해안 조석-해일 비선형성 발생양상

Hourly tide-gauge data at 10 tide stations along the West/South coasts were analysed statistically for tidesurge interaction. Interactions were found at all stations except Busan, prominently at the western tip of the South coast near Mokpo and Wando. A well-known interaction pattern which occurs at flood tide was found rarely at domestic coasts, while another pattern of the tide-modulated surge which occurs at low tide was detected frequently. In addition, a new interaction pattern which occurs at ebb tide is discovered. This pattern is found at Mokpo where the ebb dominance is prominent. Finally, the skew surge could be considered as a tool coping with such interactions. 핵심용어: tide-surge interaction, phase error, tide-modulated surge, ebb dominance, skew surge, 조석-해일 ë¹„ì„ í˜•ì„±, 위상오차, 조석변조해일, 낙조우세, 편기해일ê³

Land–sea correlations in the Australian region: post-glacial onset of the monsoon in northwestern Western Australia

Deep-sea core Fr10/95-GC17, collected offshore North West Cape at the western tip of Western Australia, is located beneath the path of the Leeuwin Current. This shallow, warm and low salinity current is an offshoot of the Indonesian Throughflow that transfers water and heat from the West Pacific Ocean into the Indian Ocean. The location is at the edge of the Indo Pacific Warm Pool, the source of large-scale transfer of moisture and heat from the ocean to the atmosphere. For this core, we combine previously published data with new research and use a revised chronology to re-examine the timing of climate change during the last 34,000 years in the tropics of northern Australia. The age model for the core is based on 15 radiocarbon dates complemented by luminescence ages and an oxygen isotope record. This study draws on an extensive range of analyses that have been performed on the core, including micropalaeontology of planktic and benthic foraminifera and coccoliths, stable isotopes analysis of foraminifera and their faunal composition, clay content, sediment composition and pollen analyses. Sea-surface and land temperatures are estimated from the foraminifer faunal analyses and from pollen spectra, respectively. The clay fraction and sediment composition and radiogenic isotopes of that fraction helped identify changes both on land and at sea: changes such as rainfall as shown by river discharge, and oceanic current tracing by neodymium, strontium and lead isotopes obtained from sediments.The most significant finding is that a major threshold was crossed at 13kaBP. Prior to that time, rainfall over NW Western Australia was low as was sea-surface temperature (SST); river discharge to the ocean was also low as a result of the lack of monsoonal activity and finally, ocean alkalinity would have been lower than at present due to the uptake of atmospheric CO2. By 13kaBP, the entire system moved away from glacial period conditions. The Indo-Australian monsoon commenced in and offshore northwestern Western Australia. SST and land temperature increased dramatically and ocean alkalinity changed due to the formation of a “barrier layer” (a low salinity cap), over the Indo Pacific Warm Pool. During the Holocene, river discharge and the land and ocean temperatures did not covary, for example, the highest rainfall did not coincide with the highest SST. Finally, the last 5ka saw a strengthening of ENSO in the region.

Vulnerability of marine benthic metapopulations: implications of spatially structured connectivity for conservation practice in the Gulf of Lions (NW Mediterranean Sea)

AbstractAimEcological connectivity is currently considered to be essential to enhance biodiversity conservation efforts and benefit adjacent areas. We evaluate the spatial structure of vulnerable marine benthic invertebrate populations based on connectivity to improve the placement of marine protected areas.LocationGulf of Lions, NW Mediterranean Sea.MethodsWe used a spatially explicit metapopulation model to explore how larval dispersal affects marine benthic invertebrate dynamics at local and regional scales. Minimum recruitment success (the proportion of larvae that settle in a site and survive between spawning and first reproduction, which is required to ensure species persistence) is proposed as a measure of vulnerability. Three contrasting simulations were constructed: closed versus connected populations, habitat loss versus recruitment failure disturbances and varying patterns of oceanographic connectivity. The rescue factor (the ratio of minimum recruitment success in connected and closed populations) quantified the decrease in vulnerability because of oceanographic connectivity.ResultsIn the Gulf of Lions, connectivity reduced population vulnerability by a rescue factor of 5.3. The minimum recruitment success for regional persistence decreased from 3% to 0.2% when species' life expectancies increased from 2 to 50 years. Connectivity enabled the spread of individuals over the entire region, but there were higher densities in sink sites, where low retention rates do not allow for local persistence (western tip of the gulf). Source sites, defined as those sites bringing metapopulation resistance to recruitment failure and stresses from habitat loss, were located in the centre of the gulf.Main conclusionsConnectivity drives the spatial structure of population density distribution and population vulnerability in the absence of any other structuring factor. In the Gulf of Lions, marine protected areas are located in population sinks; however; if protection measures were taken in the central part, populations would benefit throughout the region via the rescue effect.

The Cerro Bayo District, Chilean Patagonia: Late Jurassic to Cretaceous Magmatism and Protracted History of Epithermal Ag-Au Mineralization

Research Article| March 01, 2014 The Cerro Bayo District, Chilean Patagonia: Late Jurassic to Cretaceous Magmatism and Protracted History of Epithermal Ag-Au Mineralization* Jaime A. Poblete; Jaime A. Poblete † 1Mineral Deposit Research Unit, Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, BC, Canada †Corresponding author: e-mail, japoblet@gmail.com Search for other works by this author on: GSW Google Scholar Thomas Bissig; Thomas Bissig 1Mineral Deposit Research Unit, Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, BC, Canada Search for other works by this author on: GSW Google Scholar James K. Mortensen; James K. Mortensen 2Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, BC, Canada Search for other works by this author on: GSW Google Scholar Janet Gabites; Janet Gabites 3Pacific Centre for Isotope and Geochemical Research, Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, BC, Canada Search for other works by this author on: GSW Google Scholar Richard Friedman; Richard Friedman 3Pacific Centre for Isotope and Geochemical Research, Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, BC, Canada Search for other works by this author on: GSW Google Scholar Manuel Rodriguez Manuel Rodriguez 4Coeur South America, Av. Vitacura 5250, Of. 404 Vitacura, Santiago, Chile Search for other works by this author on: GSW Google Scholar Economic Geology (2014) 109 (2): 487–502. https://doi.org/10.2113/econgeo.109.2.487 Article history received: 22 Mar 2012 accepted: 03 Jun 2013 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jaime A. Poblete, Thomas Bissig, James K. Mortensen, Janet Gabites, Richard Friedman, Manuel Rodriguez; The Cerro Bayo District, Chilean Patagonia: Late Jurassic to Cretaceous Magmatism and Protracted History of Epithermal Ag-Au Mineralization. Economic Geology 2014;; 109 (2): 487–502. doi: https://doi.org/10.2113/econgeo.109.2.487 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEconomic Geology Search Advanced Search Abstract The Cerro Bayo low sulfidation epithermal district is located in the Aysén region, Chilean Patagonia, at the western tip of the Deseado Massif epithermal silver-gold province. Mineralization is hosted in the mainly rhyolitic fragmental successions of the Jurassic Ibáñez Formation. New biotite 40Ar/39Ar and zircon U-Pb ages together with published ages constrain the eruption of this unit to between 158 and 144 Ma. Rhyolitic domes and dikes, including Cerro Bayo proper, aligned on the prominent N-S–striking Cerro Bayo fault and intruding rocks of the Ibáñez Formation were dated by U-Pb on zircon at 146.5 ± 0.2 and 146.3 ± 0.2 Ma. Dacitic domes of 83.0 ± 0.2 and 82.6 ± 0.2 Ma (U-Pb on zircon) are present in the western part of the district at Laguna Verde. Silver and gold mineralization is hosted by steeply dipping, dominantly N to NW and subordinate W-striking quartz veins and, to a lesser extent, in breccias, which, on the basis of new adularia 40Ar/39Ar ages, were emplaced in three main episodes: (1) Mallines: ca. 144 to 142 Ma, (2) Bahía Jara and Brillantes: ca. 137 to 124 Ma, and (3) Laguna Verde: 114 to 111 Ma, overall spanning 33 m.y. Most Ag-Au has been produced from veins emplaced in the latter two episodes. Veins at Mallines and Bahía Jara are spatially related to the Cerro Bayo fault. The oldest episode of mineralization in the district is similar in age to the youngest epithermal deposits in the Deseado Massif, whereas the economically most important veins are age equivalent to skarn and polymetallic vein mineralization in the Patagonian Andes of southern Chile. The protracted history of epithermal processes at Cerro Bayo records the evolution from continental-scale extension related to the Gondwana breakup to the establishment of Andean-type arc and back-arc environments. The largely extensional tectonics throughout this period resulted in similar epithermal mineralization styles emplaced episodically over a large time interval. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Phosphorus Bioavailability and Release Potential Risk of the Sediments in the Coastal Wetland: A Case Study of Rongcheng Swan Lake, Shandong, China

Rongcheng Swan Lake, a natural coastal wetland, is connected to Rongcheng Bay of Yellow Sea, China. In this lagoon, water quality has deteriorated gradually in recent 30 years and filamentous Chaetomorpha linum have bloomed during the past five years. In present study, the concentration, fractions, and bioavailability of phosphorus (P) in surface sediments were investigated throughout the lake. In order to evaluate P retention ability of the wetland, six sediment samples from different lake regions were collected to study P adsortion kinetics, adsortion capacity and the relation to sediment properties. In Swan Lake, total P concentrations in sediments varied from 79 to 616 mg/kg, which were significantly higher in northwest region than those in southeast region. Sediment grain size and external inputs were the main factors affecting P distribution. Inorganic P concentration was obviously higher than that of organic P, and Ca–P was the important form in the sediments. Fe/Al–P showed a large spatial variation, with relatively high concentrations occurring at the northeastern corner and the western tip strongly affected by the discharge of wastewater. The adsorption isotherms were well fitted by Linear equation at low P conditions and by Langmuir equation at high initial P concentrations, respectively. The sediments in the northern and central lake had higher P adsorption capacity, while in southern lake the degree of P saturation of the sediments was high. Ammonium oxalate extractable Al, organic matter, and fine particle were important factors influencing P adsorption. In Swan Lake, algae available P (AAP) was the largest form of bioavailable P, followed by Olsen–P; moreover, AAP and Olsen–P showed significant correlations with Fe/Al–P. As a whole, TP concentration in sediments from Swan Lake was low, and the sediments at most regions had buffering ability for P in overlying water; while at the western tip of lake where macroalgal blooms frequently breakout, AAP concentration was relatively high and the sediments had higher potential for releasing P into water column.

Insights from petrography, mineralogy and U–Pb zircon geochronology into the provenance and reservoir potential of Cenozoic siliciclastic depositional systems supplying the northern margin of the Eastern Black Sea

The Eastern Black Sea is one of the few remaining underexplored hydrocarbon basins in Europe. Reservoir quality is a key risk factor in the basin. The analysis of up-dip portions of Oligocene to Pliocene depositional systems exposed around its northern and eastern margins enable the composition and provenance of sandstones within the basin to be predicted. Two major sources of quartz-rich sandstone are present: the Russian western Greater Caucasus, which became a subaerial sediment source in the Oligocene, and the East European Craton–Scythian Platform. These are predicted to form better quality reservoirs at shallow and moderate burial depths than their rock fragment-rich counterparts, due to lesser amounts of compactional porosity loss. Oligo-Miocene sandstones from the Russian western Greater Caucasus were deposited as turbidites in the Tuapse Trough. Sandstones from the East European Craton–Scythian Platform were largely trapped within the Indolo-Kuban Basin north of the Greater Caucasus. They only entered the Eastern Black Sea in large volumes from latest Miocene or Pliocene time in the region of the Kerch–Taman shelf at the western tip of the Greater Caucasus. However, it is possible that a precursor to this system supplied the Oligocene to Early Miocene reservoir sandstones within the Subbotina field. The Dziruli Massif, in western Georgia, also generated quartz-rich sandstones, but these are not thought to have entered the Black Sea.

Evolution of Strike-Slip Duplexes and Wrench-Related Folding in the Central Part of Al Jabal Al Akhdar, NE Libya

AbstractThe deformation in the central part of Al Jabal Al Akhdar, NE Libya, is dominated by E-W right-lateral strike-slip fault zones that form a conjugate system with the N-S left-lateral strike-slip faulting. The dextral wrench-dominated transpression is responsible for the formation of strike-slip duplexes, en echelon folds, and thrusts that deform the Cretaceous-Eocene sedimentary sequences. The strike-slip duplex is formed by the progressive linkage of horsetail-like structures at the western tip of the Al Bayda strike-slip fault that joined splays coming from other dextral strike-slip faults. The master linear fault branches into second-order dextral or sinistral faults that regroup into a linear single fault. Faults started from arrays of en echelon extensional/extensional-shear fractures that then coalesced into throughgoing strike-slip faults. Shortening was accompanied by significant N-S-striking left-lateral strike-slip displacements, with the development of NE- to ESE- and SW-plunging major f...

Tidal Current Energy Resources off the South and West Coasts of Korea: Preliminary Observation-Derived Estimates

In this study we estimate the prospective tidal current energy resources off the south and west coasts of Korea and explore the influence of modeling tidal current energies based on 15-day versus month-long data records for regimes with pronounced perigean/apogean influences. The tidal current energy resources off southern and western Korea were calculated using 29-day in situ observation data from 264 stations. The resultant annual energy densities found at each station were categorized into six groups, with a greater percentage of sites falling into the lower-energy groups: 1.1% for >10 MWh·m−2; 2.7% for 5 to 10 MWh·m−2; 6.8% for 3 to 5 MWh·m−2; 9.1% for 2 to 3 MWh·m−2 and 80.3% for <2 MWh·m−2. Analysis shows that the greatest concentration of high annual energy densities occurs in the Jeonnam Province coastal region on the western tip of southwest Korea: 23 MWh·m−2 at Uldolmok, 15 MWh·m−2 at Maenggol Sudo, 9.2 MWh·m−2 at Geocha Sudo and 8.8 MWh·m−2 at Jaingjuk Sudo. The second highest annual energy density concentration, with 16 MWh·m−2, was found in Gyudong Suro, in Gyeonggi Province’s Gyeonggi Bay. We then used data from the 264 stations to examine the effect of perigean and apogean influences on tidal current energy density evaluations. Compared to derivations using month-long records, mean annual energy densities derived using 15-day perigean spring-neap current records alone overestimate the annual mean energy by around 10% whereas those derived using only the apogean records underestimate energy by around 12%. In particular, accuracy of the S2 contribution to the energy density calculations is significantly affected by use of the 15-day data sets, compared to the M2 component, which is relatively consistent. Further, annual energy density estimates derived from 29-day records but excluding the N2 constituent underestimate the potential resource by about 5.4%. Results indicate that one month of data is required to accurately estimate tidal current energy in regimes showing pronounced perigean and apogean differences in spring-neap tidal current patterns and that inclusion of the N2 constituent in calculations is preferable. This finding has widespread applicability for green energy resource assessments, for example, in regions of the Unites States Atlantic coast and in New Zealand.

The westward intrusion of south Pacific water at the western tip of the New Guinea Island

Fromthe eastern Indonesian cruise from November 14 to 23, 2007, CTD (conductivity, temperature, depth profiler) /ADCP (acoustic Doppler current profiler)casting and seawater sampling were done at 25 stations around Waigeo Island near New Guinea Island. It was found overall westward intrusion of the south Pacific waters into the Seram Sea and southward spreading of the north and south Pacific waters into the Seram Sea. There is westward residual flow along the channel between Waigeo and New Guinea within upper 200 m with the maximum speed up to 50 cm/s, and much weaker eastward flow in the lower layer (< 10 cm/s) due to blocking by the shallow sill at the west of the Dampier Strait. The abrupt change of bottom topography induces active horizontal and vertical mixing which results in a three-layered current system with a major through-flow of −0.99 Sv (Sv = 106 m3/s) into the Seram Sea; the transports in the upper and the lower layers are −1.14 Sv and −0.24 Sv (westward), respectively, and in the middle there is a return flow with the transport of +0.39 Sv (eastward).

Effect of Different Concentrations of Detergent on Dissolved Oxygen Consumption in Anabas testudineus

Kerala, on the South Western tip of Peninsular India is blessed with the South western and South Eastern monsoon which contributes to its vast fresh water bodies. But pollution of these water bodies has created physiological stress on its aquatic fauna. Among various forms of pollution in water bodies, detergent pollution has an immediate and detrimental effect on the aquatic fauna. Anabas testudineus, a common fresh water fish in Kerala was used in our study to determine the effect of detergent pollution on the fish's breathing. Three different concentrations of a popular brand of detergent were prepared and the amounts of Dissolved Oxygen consumed by fishes exposed to the detergent were determined using Winkler's method. Our study demonstrated that Dissolved Oxygen consumption in Anabas testudineus increases in the presence of detergent. This is due to the stress caused by the detergent on the normal physiological activities of the fish. Draining of domestic sewage containing detergents into water bodies adversely affect its aquatic fauna.

Subsurface structure of Umaoi-hills that is located at western tip of fold-and-thrust belt, Hokkaido, JAPAN.

Subsurface structure of Umaoi-hills that is located at western tip of fold-and-thrust belt, Hokkaido, JAPAN.

The January 2010 Efpalion earthquakes (Gulf of Corinth, Central Greece): earthquake interactions and blind normal faulting

On 18 January 2010, 15:56 UTC, a Mw = 5.1 (National Observatory of Athens; NOA) earthquake occurred near the town of Efpalion (western Gulf of Corinth, Greece), about 10 km to the east of Nafpaktos, along the north coast of the Gulf. Another strong event occurred on 22 January 2010, 00:46 UTC with Mw = 5.1 (NOA) approximately 3 km to the NE of the first event. We processed the seismological and geodetic data to examine fault plane geometry, dip direction, and earthquake interactions at the western tip of the Corinth rift. Our data include relocated epicenters of 1,760 events for the period January–June 2010 and daily global positioning system observations from the Efpalio station for the period 1 December 2009–1 March 2010. We suggest that the first event ruptured a blind, north-dipping fault, accommodating north–south extension of the Western Gulf of Corinth. The dip direction of the second event is rather unclear, although a south dip plane is weakly imaged in the post-22 January 2010 aftershock distribution. A Coulomb stress model based on homogeneous slip distribution of the first event showed static stress triggering of the second event of the order of 22–34 KPa that was transferred along the plane of failure. We also point out the existence of north dipping, high-angle faults at 10–15 km depths, which were reactivated because of Coulomb stress transfer, to the west and south of Efpalion. The January 2010 earthquakes ended a 15-year-old quiescence in that area of the Gulf. The crustal volume near Efpalion was also characterized by b values in the range 0.6–0.8 (1970–2010 period).

Fault kinematics in northern Central America and coupling along the subduction interface of the Cocos Plate, from GPS data in Chiapas (Mexico), Guatemala and El Salvador

New GPS measurements in Chiapas (Mexico), Guatemala and El Salvador are used to constrain the fault kinematics in the North America (NA), Caribbean (CA) and Cocos (CO) plates triple junction area. The regional GPS velocity field is first analysed in terms of strain partitioning across the major volcano-tectonic structures, using elastic half-space modelling, then inverted through a block model. We show the dominant role of the Motagua Fault with respect to the Polochic Fault in the accommodation of the present-day deformation associated with the NA and CA relative motion. The NA/CA motion decreases from 18–22 mmyr-’1 in eastern Guatemala to 14–20 mmyr-’1 in central Guatemala (assuming a uniform locking depth of 14–28 km), down to a few millimetres per year in western Guatemala. As a consequence, the western tip of the CA Plate deforms internally, with ≃9 mmyr-’1 of east–west extension (≃5 mmyr-’1 across the Guatemala city graben alone). Up to 15 mmyr-’1 of dextral motion can be accommodated across the volcanic arc in El Salvador and southeastern Guatemala. The arc seems to mark the northern boundary of an independent forearc sliver (AR), pinned to the NA plate. The inversion of the velocity field shows that a four-block (NA, CA, CO and AR) model, that combines relative block rotations with elastic deformation at the block boundaries, can account for most of the GPS observations and constrain the overall kinematics of the active structures. This regional modelling also evidences lateral variations of coupling at the CO subduction interface, with a fairly high-coupling (≃0.6) offshore Chiapas and low-coupling (≃0.25) offshore Guatemala and El Salvador.