scholarly journals FORMATION OF T0MB0L0 AT THE WEST COAST OF IWO-JIMA

1984 ◽  
Vol 1 (19) ◽  
pp. 96
Author(s):  
Toshiyuki Shigemura ◽  
Jouji Takasugi ◽  
Yoshihiro Komiya
Keyword(s):  
West Coast ◽  
Field Measurements ◽  
Northern Coast ◽  
The West ◽  
Sea Floor ◽  
Short Period ◽  
Variation Rate ◽  
Induced Currents ◽  
The One ◽  
Dominant Direction

This paper intends to clarify why and how such a huge tombolo having a surface area of 1,700,000 m2 has been formed at the west coast of Iwojima for relatively short period of 33 years after 1945. Analyses are performed on various data obtained through literature survey and field measurements to determine the growth rate of tombolo and variation rate of shore and sea floor surrounding the island. Model tests are also made on the formation of tombolo. The followings are the conclusions derived through the analyses: (1). Source of the sediments is the one produced at the northern part of island where sea floor has been lifting at a rate exceeding 30 cm per year, (2). Waves with dominant direction of N to NE which appear in fall and winter erode the northern coast and currents induced by these waves carry these sediments southward along both coasts of the island. (3). Waves with dominant direction of S to SE which appear in summer and their induced currents carry the sediments northward along both coasts of the island.

Stratocumulus Clouds at the West Coast of South America: Observations of Diurnal and Seasonal Cycle

2020 ◽  
Author(s):  
Jan H. Schween ◽  
Sarah Westbrook ◽  
Ulrich Löhnert
Keyword(s):  
South America ◽  
Liquid Water ◽  
West Coast ◽  
Seasonal Pattern ◽  
Radiation Budget ◽  
Wind Component ◽  
Northern Coast ◽  
The West ◽  
Long Term Study ◽  
Stratocumulus Clouds

<p>Marine stratocumulus clouds of the eastern Pacific play an essential role in the Earth's energy and radiation budget. Parts of these clouds off the west coast of South America form the major source of water to the hyper-arid area at the northern coast of Chile. Within the DFG collaborative research center 'Earth evolution at the dry limit', for the first time, a long-term study of the vertical structure of clouds and their environment governing the moisture supply to the coastal part of the Atacama is available.</p><p>Three state of the art ground based remote sensing instruments were installed for one year at the airport of Iquique/Chile (20.5°S, 70.2°W, 56m a.s.l.) in close cooperation with Centro del Desierto de Atacama (Pontificia Universidad Católica de Chile). The instruments provide vertical profiles of wind, turbulence and temperature, as well as integrated values of water vapor and liquid water. Instrument synergy provides vertical cloud structure information.</p><p>We observe a land-sea circulation with a super-imposed southerly wind component. Highest wind speeds can be found during the afternoon. Clouds show a distinct seasonal pattern with a maximum of cloud occurrence during winter (JJA) and a minimum during summer (DJF). Clouds are higher and vertically less extended in winter than in summer. Liquid water path shows a diurnal cycle with highest values during night and morning hours and lowest values during noon. Furthermore, the clouds contain much more liquid water in summer. The turbulent structure of the boundary layer, together with the temperature profile, can be used to characterize the mechanism driving the cloud life cycle.</p>

scholarly journals Stratabound scheelite and stratiform tourmalinites in the Archaean Malene supracrustal rocks, southern West Greenland

1987 ◽  
Vol 156 ◽  
pp. 1-26
Author(s):  
P.W.U Appel ◽  
A.A Garde
Keyword(s):  
West Coast ◽  
Stream Sediment ◽  
Amphibolite Facies ◽  
The West ◽  
Late Archaean ◽  
Sea Floor ◽  
West Greenland ◽  
Sediment Sampling ◽  
Geological Map ◽  
Boron Complexes

The Malene supracrustal rocks form large enclaves in the late Archaean Nûk gneisses within an area of at least 36 000 km2 on the west coast of Greenland and have been repeatedly deformed and metamorphosed under amphibolite facies conditions. Stream sediment sampling has shown that scheelite occurs in the supracrustal enclaves throughout the area. It occurs stratabound in amphibolites, micaceous quartzites, siliceous cordierite-bearing metasediments and tourmalinites. A detailed geological map has been made of the central part of Store Malene mountain close to Nuuk. Banded metavolcanic Malene amphibolites and siliceous cordierite-bearing metasediments contain stratiform tourmalinites, often with appreciable scheelite, in addition to common accessory tourmaline. The tourmaiinites predate the earliest recognisable phase of deformation as well as prominent simple pegmatites. The tourmaline probably originated as primary sea floor precipitates, and the primary or diagenetic tourmaline crystals were later overgrown with tourmaline during metamorphism. The scheelite and tourmaline are probably syngenetic and of submarine exhalative origin, and boron complexes may have played a role in transporting tungsten in hot brines.

scholarly journals Field Application for Evaluating Vertical Stress of Soil in Multilayered Ground

2021 ◽  
Vol 21 (4) ◽  
pp. 151-157
Author(s):  
Jiseong Kim ◽  
Eun-Sang Im ◽  
Gichun Kang
Keyword(s):  
West Coast ◽  
Field Measurements ◽  
Field Application ◽  
Vertical Stress ◽  
Soft Ground ◽  
Clay Layer ◽  
The West ◽  
Ground Settlements ◽  
Overconsolidated Clay

In the west coast and the coast of Busan, at several locations, an overconsolidated layer exists above the soft ground. For soft ground with an upper overconsolidated clay layer, significant errors exist between the design and the actual settlements in the field. For multilayered ground, although Boussinesq's theory is applied, significant errors still exist. In this study, ground settlements in the overconsolidated clay layer were predicted using the Burmister and Hirai method. Based on comparisons with field measurements, it was confirmed that the accuracy could be increased by more than 90%.

Hydrographic Charting and Oceanography on the West Coast of Canada from the Eighteenth Century to the Present Day

1972 ◽  
Vol 73 ◽  
pp. 75-83
Author(s):  
Robert W. Sandilands
Keyword(s):  
British Columbia ◽  
Eighteenth Century ◽  
Pacific Northwest ◽  
West Coast ◽  
Vancouver Island ◽  
The West ◽  
Special Place ◽  
The Pacific ◽  
Short Period ◽  
Formative Years

Those participating in this Congress are aware of the leadership of Rear-Admiral George Henry Richards in mounting the Challenger Expedition, which he himself regarded as the crowning achievement of his career. However, he also has a very special place in the history and development of British Columbia and it can fairly be said that his work in the Pacific Northwest was the major achievement of his sea-going career. His service on the coast covered the short period 1857 to 1863, but these were formative years in the development of the west coast colonies of Vancouver Island and British Columbia.

scholarly journals French Colonial Expansion in West Africa, The Sudan, and the Sahara

1911 ◽  
Vol 5 (3) ◽  
pp. 353-373
Author(s):  
Norman Dwight Harris
Keyword(s):  
West Africa ◽  
West Coast ◽  
The West ◽  
Colonial State ◽  
Senegal River ◽  
Colonial Expansion ◽  
Dark Continent ◽  
Colonial Empire ◽  
French Colonial ◽  
The One

The conclusion of a definite treaty of diplomatic alliance between France and Morocco, in February, 1910, marks one of the last steps in a long series of moves to establish for France a vast colonial empire in the Dark Continent. Between the years 1830 and 1850, France acquired the whole of Algeria and Constantine. In 1881 she annexed Tunisia; and, in the ten years that followed, she participated with Germany, Great Britain and Italy, in the race for territory in Africa. But it is only within the past twenty years that she has successfully created a great colonial state there.French colonial enterprise in Africa began in 1637, when Claude de Rochefort built fort St. Louis at the mouth of the Senegal river on the west coast and explored the interior for 100 miles. He was followed during the 18th and early 19th centuries by other intrepid explorers who made settlements at Millicourie on the Guinea coast and at Assinié and Grand Bassam on the Ivory Coast, and who penetrated further and further into the interior until the valiant Réné Caille, after marvelous adventures, reached Timbuktu, near the Upper Niger, in 1837. The French holdings on the Senegal were extended and consolidated into an effective base for future operations by the energetic General Faidherbe from 1854 to 1865, who added the Oulof country as far south as Cape Verde and the kingdom of Cayore, and built the harbor at Darkar. He was the first to recognize the possibilities of West Africa as a colonial center. “Our possession on the West Coast,” he wrote to the Colonial Office, “is possibly the one of all our colonies that has before it the greatest future; and it deserves the whole sympathy and attention of the Empire.”

SUBMERGED CORAL REEFS, WEST COAST OF BARBADOS, WEST INDIES

1967 ◽  
Vol 4 (3) ◽  
pp. 461-474 ◽  
Author(s):  
I. G. Macintyre
Keyword(s):  
Coral Reefs ◽  
Sea Level ◽  
West Coast ◽  
Deep Sea ◽  
West Indies ◽  
Sedimentary Rocks ◽  
Average Depth ◽  
The West ◽  
Sea Floor ◽  
Barrier Reefs

Seven sonar profiles of the sea floor were made at 3–mile intervals approximately perpendicular to the west coast of Barbados, W.I. Evidence from these profiles, first-hand observations, and deep-sea camera photographs indicate that two submerged barrier reefs parallel the coast at approximate depths of 70 and 230 ft. A trench is present in a deeper part of the sloping sea floor behind a small ridge at an average depth of 619 ft.The positions of the submerged barrier reefs probably were controlled by pauses in the post-Pleistocene eustatic rise in sea level. The First Ridge was established on an erosional terrace that could have been cut during a stillstand between 12 500 and 11 500 years B.P. The Second Ridge may have been established on a narrow ledge eroded during a stillstand between 16 500 and 15 000 years B.P. The trench appears to have resulted from faulting or submarine outcropping of Tertiary sedimentary rocks.

Stratocumulus Clouds at the West Coast of South America: Observations of Diurnal and Seasonal Cycle

2021 ◽  
Author(s):  
Jan H. Schween ◽  
Ulrich Löhnert ◽  
Sarah Westbrook
Keyword(s):  
South America ◽  
Liquid Water ◽  
West Coast ◽  
Seasonal Pattern ◽  
Radiation Budget ◽  
Wind Component ◽  
Northern Coast ◽  
The West ◽  
Long Term Study ◽  
Stratocumulus Clouds

<p>Marine stratocumulus clouds of the eastern Pacific play an essential role in the Earth's energy and radiation budget. Parts of these clouds off the west coast of South America form the major source of water for the Atacama, a hyper-arid area at the northern coast of Chile. Within the DFG collaborative research center 'Earth evolution at the dry limit', for the first time, a long-term study of the vertical structure of clouds and their environment governing the moisture supply to the coastal part of the Atacama is available.</p><p>Three state of the art ground based remote sensing instruments were installed for one year at the airport of Iquique/Chile (20.5°S, 70.2°W, 56m a.s.l.) in close cooperation with the Centro del Desierto de Atacama (Pontificia Universidad Católica de Chile). The instruments provide vertical profiles of wind, turbulence and temperature, as well as integrated values of water vapor and liquid water. The cloudnet algorithm is used to exploit instrument synergy and provides vertical cloud structure information.</p><p>We observe a land-sea circulation with a super-imposed southerly wind component. Highest wind speeds can be found during the afternoon. Clouds show a distinct seasonal pattern with a maximum of cloud occurrence during winter (JJA) and a minimum during summer (DJF). Clouds are higher and vertically less extended in winter than in summer. Liquid water path shows a diurnal cycle with highest values during night and morning hours and lowest values during noon. Furthermore, the clouds contain much more liquid water in summer. The turbulent structure of the boundary layer, together with the temperature profile, can be used to characterize the mechanism driving the cloud life cycle.</p>

Recent discoveries at Ostia

1912 ◽  
Vol 2 ◽  
pp. 153-194
Author(s):  
Thomas Ashby
Keyword(s):  
West Coast ◽  
Seventh Century ◽  
The West ◽  
The One

The west coast of Italy between the gulf of Spezia, once the harbour of Luna, and the bay of Gaeta does not at the present day offer a single safe anchorage for ships of any size, and even in early days, when ships were smaller, its harbours and landing places must have seemed very deficient. The cities of south-western Etruria had indeed developed a flourishing seaborne trade by the seventh century B.C. when they were importing freely from Greece, but the ports of their two leading towns, Tarquinii and Caere, which seem to have been at Graviscae and Pyrgi, were merely roadsteads. Strabo, in his summary of the ports along this littoral, mentions none between Monte Argentario and Ostia, and none again between Ostia and the bay of Gaeta. Such ports as there ever were, are of later origin. Centumcellae, the modern Civitavecchia, is a foundation of Trajan; the harbour of Antium, such as it was, was due to Nero, and the port of Terracina is the work of Pius. Even Ostia itself was in Strabo's time deemed a bad harbour and the Tiber estuary hard to enter. Good or bad, however, it was the one approach to a natural harbour on all this coast.

scholarly journals GEOMORPHOLOGICAL STUDIES OP THE ESTUARY OF RIVER NETRA7ATI NEAR MANGALORE

1974 ◽  
Vol 1 (14) ◽  
pp. 76
Author(s):  
E.J. John ◽  
K.P. Cheryan
Keyword(s):  
Sediment Transport ◽  
West Coast ◽  
Combined Effect ◽  
Ocean Currents ◽  
The West ◽  
River Flows ◽  
West Coast Of India ◽  
Number Of Factors ◽  
Wave Conditions ◽  
The One

A number of factors such as wave conditions, tides, river flows, sediment charge, and ocean currents affect the features of an estuary. The understanding of the morphology of an estuary is essential on purely scientific considerations as well as applied to harbours. An attempt is made to study these inter-related and unsteady features and their combined effect on an estuary qualitatively. The estuary selected for the study is the one near Mangalore on the West Coast of India at latitude 12 51' north and longitude 74° 50' east, where two rivers, viz., river Netravati and river Gurpur meet together and join the sea. An effort is made to analyse the changes in the estuary in terms of prevailing wave conditions, river flows and sediment transport.

Fault geometry and rupture patterns of the 2018 Lombok earthquakes – complex thrust faulting in a volcanic retro-arc setting

2020 ◽  
Author(s):  
Shengji Wei ◽  
Karen Lythogoe ◽  
Muzli Muzli ◽  
Andri Dian Hugraha ◽  
Kyle Bradley ◽  
...  
Keyword(s):  
Thermal Structure ◽  
Earthquake Sequence ◽  
Depth Range ◽  
Northern Coast ◽  
Rupture Directivity ◽  
The West ◽  
Volcanic System ◽  
The North ◽  
Brittle Ductile Transition ◽  
Short Period

<p>The 2018 Lombok earthquake sequence, which took place ~10km to the north of the Rinjani volcano on the Flores thrust fault, are distributed beneath the northern coast of the island, composing of two Mw6.4 and two Mw6.9 earthquakes and numerous aftershocks. The first Mw6.4 earthquake was followed by the first Mw6.9 event in a week, which was located only a few kilometers to the west of the Mw6.4 event, characterized with strong westwards rupture directivity and multiple asperities (rougher source time function). Two weeks later, the second Mw6.4 event took place a few km to the east of the first Mw6.4 event and triggered the second Mw6.9 event 12 hours later. In contrast, the second Mw6.9 ruptured towards east with a single major asperity, with a centroid depth of ~18km, ~5km shallower than the first Mw6.9 event. The seismicity was well captured by 7 broadband stations and 6 short period nodes deployed just before the first Mw6.9 event, mostly concentrated within a depth range of 5km. Relocated seismicity shows shallower depth to the west and deeper to the east, in consistent with the coseismic rupture of the largest events. Aftershocks are shallowest below the volcano due to an elevated Brittle-Ductile-Transition (BDT) zone depth controlled by the thermal structure. A few anomalous earthquakes were identified between the M<sub>w</sub>6.9 events below the BDT zone that could be related to the basaltic conduit of the volcano. Several sets of repeating earthquakes were identified and are mostly located in the rupture area of the first Mw6.9 event, indicating a highly heterogeneous friction on the fault that is probably caused by to the stronger thermal gradient compared with the second Mw6.9 event. The earthquake sequence highlights the strong interaction between the volcanic system and the tectonic faulting process. </p>

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