scholarly journals A LABORATORY AND FIELD STUDY ON 2DH SPECTRAL WAVE TRANSFORMATION IN MUDDY ENVIRONMENTS

2012 ◽  
Vol 1 (33) ◽  
pp. 39
Author(s):  
Mohsen Soltanpour ◽  
S. Abbas Haghshenas ◽  
Tomoya Shibayama
Keyword(s):  
Wave Spectrum ◽  
Field Measurements ◽  
Wave Model ◽  
Transformation Model ◽  
Wave Transformation ◽  
S Wave ◽  
North West ◽  
The North ◽  
Wave Basin ◽  
The Persian Gulf

The present paper offers a set of wave basin experiments on muddy beds together with field measurements data at Hendijan Mud Coast in the north-west corner of the Persian Gulf in order to investigate the 2DH spectral wave transformation over muddy beds. A dissipation model was added to REF/DIF S wave model to develop a numerical wave spectrum transformation model for muddy beaches. The proposed model was utilized to analyze the experimental and field measurements data on muddy beds. The simulated wave spectra over-mud bed are in fair agreement with the measurements.

Seismotectonics of the Ionian-Akarnania Block (IAB) and Western Greece deduced from a local seismic deployment.

2020 ◽  
Author(s):  
Antoine Haddad ◽  
Athanassios Ganas ◽  
Ioannis Kassaras ◽  
Matteo Lupi
Keyword(s):  
Fault Zone ◽  
Velocity Model ◽  
Focal Mechanisms ◽  
Seismogenic Zone ◽  
The South ◽  
S Wave ◽  
North West ◽  
The North ◽  
Short Period ◽  
Western Greece

<p>From July 2016 to May 2017, we deployed a local seismic network composed of 15 short-period seismic stations to investigate the ongoing seismotectonic deformation of Western Greece with emphasis on the region between Ambrakikos Gulf (to the north) and Kyparissia (to the south). The network was deployed to investigate the behavior of key crustal blocks in western Greece, such as the Ionian-Akarnania Block (IAB).</p><p>After applying automatic P- and S- wave phase picking we located 1200 local earthquakes using HypoInverse and constrained five 1D velocity model by applying the error minimization technique. Events were relocated using HypoDD and 76  focal mechanisms were computed for events with magnitudes down to M<sub>L</sub> 2.3 using first motion polarities.</p><p>We combined the calculated focal mechanisms and the relocated seismicity to shed light on the IAB block boundaries. Three boundaries highlighted by previous studies were also evidenced :</p><p>-The north-west margin of the block, the Cephalonia Transform Fault, Europe‘s most active fault. NW-striking dextral strike-slip motion was recognized for this fault near the Gulf of Myrtos and the town of Fiskardo.</p><p>- The south-east margin is the Movri-Amaliada right-lateral Fault Zone, activated during the Movri Mt. M<sub>w</sub> 6.4 earthquake sequence.</p><p>- The Ambrakikos Gulf (a young E-W rift) and the NW-striking left-lateral Katouna-Stamna Fault zone depict the north and north-eastern margins of the IAB block.</p><p>Seismicity lineaments and focal mechanisms define theKyllini-Cephalonia left-lateral fault, which is also highlighted by bathymetry data. We interpret this fault as the south-western margin of IAB separating an aseismic area observed between Cephalonia and Akarnania from a seismogenic zone north of Zakynthos Island and bridging NW Peloponnese with Cephalonia.</p>

Projected Changes in the Occurrence of Extreme and Rogue Waves in Future Climate in the North Atlantic

2017 ◽  
Author(s):  
Odin Gramstad ◽  
Elzbieta Bitner-Gregersen ◽  
Erik Vanem
Keyword(s):  
North Atlantic ◽  
Wave Spectrum ◽  
Wave Model ◽  
Rogue Waves ◽  
Wave Climate ◽  
Future Climate ◽  
The North ◽  
Wave Parameters ◽  
The Future ◽  
The North Atlantic

We investigate the future wave climate in the North Atlantic with respect to extreme events as well as on wave parameters that have previously not been considered in much details in the perspective of wave climate change, such as those associated with occurrence of rogue waves. A number of future wave projections is obtained by running the third generation wave model WAM with wind input derived from several global circulation models. In each case the wave model has been run for the 30-year historical period 1971–2000 and the future period 2071–2100 assuming the two different future climate scenarios RCP 4.5 and RCP 8.5. The wave model runs have been carried out by the Norwegian Meteorological Institute in Bergen, and the climate model result are taken from The Coupled Model Intercomparison Project phase 5 - CMIP5. In addition to the standard wave parameters such as significant wave height and peak period the wave model runs provided the full two-dimensional wave spectrum. This has enabled the study of a larger set of wave parameters. The focus of the present study is the projected future changes in occurrence of extreme sea states and extreme and rogue waves. The investigations are limited to parameters related to this in a few selected locations in the North Atlantic. Our results show that there are large uncertainties in many of the parameters considered in this study, and in many cases the different climate models and different model scenarios provide contradicting results with respect to the predicted change from past to future climate. There are, however, some situations for which a clearer tendency is observed.

X. Sennacherib's Campaigns on the North-West and his Work at Nineveh

1910 ◽  
Vol 42 (2) ◽  
pp. 387-411
Author(s):  
T. G. Pinches
Keyword(s):  
Persian Gulf ◽  
British Museum ◽  
Considerable Importance ◽  
Historical Document ◽  
North West ◽  
Asiatic Society ◽  
The North ◽  
The Persian Gulf ◽  
Royal Asiatic Society

THE British Museum having been fortunate enough to acquire a new historical document from Assyria of considerable importance, it has been thought that (not withstanding that an excellent translation and commentary upon it, from the pen of the copyist of the text, Mr. L. W. King, of the British Museum, has been published) a few notes concerning it would not be without interest to the readers of the Journal of the Royal Asiatic Society, and more particularly those whose studies deal with the pre-Christian Semitic East, especially the tract lying north-west of the Persian Gulf.

scholarly journals Rupture process of the 2014 Orkney earthquake, South Africa

2017 ◽  
Vol 17 (4B) ◽  
pp. 75-81
Author(s):  
Okubo Makoto ◽  
Artur Cichowicz ◽  
Hiroshi Ogasawara ◽  
Osamu Murakami ◽  
Shigeki Horiuchi
Keyword(s):  
South Africa ◽  
Strong Motion ◽  
Rupture Process ◽  
Gold Mine ◽  
Distribution Analysis ◽  
S Wave ◽  
Aftershock Distribution ◽  
North West ◽  
The North ◽  
Initial Rupture

An earthquake has occurred at 10:22:33 UT on 5 August 2014 in the Klerksdorp district, the North West province of South Africa. Its hypocenter is located beneath an Orkney town, where more than 10 gold mines exist. The Council for Geoscience (CGS) in South Africa reported that the magnitude and depth was ML5.5 and 4.7 km, respectively. CGS has been operating 17 surface seismic acceleration stations with 10 km interval in average, and obtained continuous acceleration seismograms through the time of the earthquake and following aftershocks. Using these seismograms, we analyzed the mainshock rupture process of this earthquake. Analyzing these seismograms, we found the ‘initial rupture’ with a Richter scale approximately 4 has occurred 0.3 sec before mainshock. Furthermore, by applying detailed aftershock distribution analysis, we found most of aftershocks occurred surrounding upper and southern part of mainshock rupture area, including initial rupture hypocenter. In order to understand detailed rupture process of this event, we surveyed for strong motion generating area (SMGA) of mainshock by applying Isochrones backprojection method (IBM) to the mainshock S wave waveforms. SMGA distribution seems to fill the vacant space of the aftershock distribution and initial rupture’s hypocenter. And we also found that a horizontal layered seismic vacancy exists between aftershocks with gold mine blastings. This fact implies mainshock rupture did not extent up to gold mine.

scholarly journals Numerical simulation of a tsunami event during the 1996 volcanic eruption in Karymskoye lake, Kamchatka, Russia

2010 ◽  
Vol 10 (11) ◽  
pp. 2359-2369 ◽  
Author(s):  
T. Torsvik ◽  
R. Paris ◽  
I. Didenkulova ◽  
E. Pelinovsky ◽  
A. Belousov ◽  
...  
Keyword(s):  
Wave Speed ◽  
Field Measurements ◽  
Wave Model ◽  
Tsunami Source ◽  
Wave Runup ◽  
Underwater Explosions ◽  
North Shore ◽  
The North ◽  
Order Of Magnitude ◽  
South Shore

Abstract. Karymskoye caldera lake is a nearly circular body of water with a diameter of approximately 4 km and a depth of up to 60 m. The sublacustrine, Surtseyan-type eruption in the lake on 2–3 January 1996 included a series of underwater explosions. A field survey conducted the following summer showed signs of tsunami wave runup around the entire coastline of the lake, with a maximum of 29 m runup at the north shore near the source of the eruption, and 2–5 m runup at locations on the east and south shore far away from the source. The tsunami has been simulated using the numerical long wave model COULWAVE, with input from reconstructed realistic pre-eruption bathymetry. The tsunami source was chosen as suggested by Le Mehaute (1971) and Mirchina and Pelinovsky (1988). The initial wave was prescribed by a parabolic shape depression with a radius of R=200 m, and a height of 23 m at the rim of the parabola. Simulations were conducted to show principle directions for wave propagation, wave speed and arrival time for the leading wave group at the shore, and the distribution of wave height throughout the lake. Estimated result for wave runup are of the same order of magnitude as field measurements, except near the source of the eruption and at a few locations where analysis show significant wave breaking.

The ‘Hearth of Domestication’? Transitions to Farming in South-West Asia

2006 ◽  
Author(s):  
Graeme Barker
Keyword(s):  
Persian Gulf ◽  
Mediterranean Coast ◽  
North West ◽  
Hill Country ◽  
Anatolian Plateau ◽  
The North ◽  
South West ◽  
The Mediterranean ◽  
Western Side ◽  
The Persian Gulf

The principal focus of this chapter is the classic zone of early farming research from the 1960s onwards, the so-called ‘hilly flanks of the Fertile Crescent’ in South-West Asia (Fig. 4.1). This region is normally defined as the arc of hill country to the west of the Syrian desert and to the north and east of the Tigris and Euphrates valleys. The western side of the arc begins east of the Nile in the Sinai and the Gulf of Arabah on the southern border of Israel and Jordan; it continues northwards as the hill country on either side of the Jordan rift valley in Israel, Palestine, Lebanon, western Jordan, and western Syria (the so-called ‘Levantine corridor’); and extends westwards to the Mediterranean littoral. The northern sector is formed by the Taurus mountains along the southern edge of the Anatolian plateau, which curve eastwards from the Mediterranean coast in northern Syria to form the present-day Syrian–Turkish border. The eastern sector consists of the Zagros mountains, running south-eastwards from eastern Turkey and north-west Iran to the Persian Gulf, forming the Iraq–Iran border for most of their length, and continuing in south-west Iran beyond the Persian Gulf towards the Straits of Hormuz. The region also embraces adjacent zones: the alluvial plains of the Tigris and Euphrates rivers and the vast tracts of steppe and desert country separating them from the Levantine, Taurus, and Zagros upland systems; the Anatolian plateau to the north of the Taurus, within modern Turkey; and the Iranian plateau east of the Zagros, within modern Iran. The archaeological literature commonly uses the term Near East to describe the main region of interest, with the Levant for its western side (a term also used in this chapter), and South-West Asia for the eastern side, but the entire region is more correctly termed South-West Asia. The upland areas of the region mostly receive more than 200 millimetres of rainfall a year, which is the minimum required for growing cereals without irrigation. Rainfall decreases drastically moving out into the steppe and desert zones.

A Methodology to Simulate Floating Offshore Operations Using a Design Wave Theory

2005 ◽  
Vol 128 (4) ◽  
pp. 304-313 ◽  
Author(s):  
Lee O’Neill ◽  
Emmanuel Fakas ◽  
Mark Cassidy
Keyword(s):  
Oil And Gas ◽  
Wave Model ◽  
Wave Theory ◽  
Contact Forces ◽  
Efficient Manner ◽  
North West ◽  
The North ◽  
Large Numbers ◽  
Cost Efficient ◽  
Offshore Operations

Numerical techniques are extensively used to predict vessel motions and associated contact forces for offshore operations such as lift and floatover deck installations. The accuracy of such predictions however is highly dependent on the comprehensive modeling of sea state conditions, which is often limited by computational power and time constraints. A time-efficient methodology, suitable for modeling large numbers of installation sea states, is developed to alleviate this problem. The methodology is based on the Constrained New Wave model which has been previously used to overcome similar problems. However this has only been for individual, extreme storm conditions. The accuracy, time-efficiency, and practicality of the revised methodology is demonstrated by means of direct comparison of simulation results obtained for a floatover deck installation on the North West Shelf of Australia. The ability to perform a large number of simulations in a time and cost efficient manner is of paramount importance in assessing the system limitations to varying installation conditions, a case that has always been challenging to designers during the development of oil and gas projects. Such flexibility improves confidence in the overall system, necessary for the accurate assessment of the commercial viability of marginal developments.

Distribution of Jet Streams at 200 mb. in the Middle East

1967 ◽  
Vol 20 (4) ◽  
pp. 397-404
Author(s):  
A. F. Crossley ◽  
I. N. Parkinson
Keyword(s):  
Middle East ◽  
North Atlantic ◽  
Eastern Mediterranean ◽  
Jet Streams ◽  
North West ◽  
The North ◽  
European Area ◽  
The North Atlantic ◽  
The Mediterranean ◽  
The Persian Gulf

1. INTRODUCTION. The distribution of jet streams over the North Atlantic, Europe and the Mediterranean for the two years 1957–8 was described in an earlier paper (Crossley, 1961); the present paper extends the study to the area which is here referred to somewhat loosely as the Middle East —it extends between latitudes 40° N. and 10;° N., and from longitude 30° E. to 90° E. in the north but to only 65° E. in the south (Fig. 1). The aircraft trunk routes intersecting this area include those from the Eastern Mediterranean across Arabia and the Persian Gulf to West Pakistan and north-west India.The jet streams which affect the Atlantic-European area in the upper troposphere are mostly of the ‘polar’ type with a core in the neighbourhood of 300 mb. so that they can be conveniently located as a rule on the contour charts for 300 mb.; in the Mediterranean region and in the corresponding latitudes of the North Atlantic the westerly subtropical jet stream is also concerned and charts for both 300 and 200 mb.

Near-surface Stokes drift in operational wave forecast

2021 ◽  
Author(s):  
Carsten Hansen
Keyword(s):  
Wave Spectrum ◽  
Wave Model ◽  
Stokes Drift ◽  
Wave Number ◽  
Computational Time ◽  
Near Surface ◽  
Wave Modelling ◽  
Wavewatch Iii ◽  
North West ◽  
Wave Forecast

<p><strong>Near-surface Stokes drift in operational wave forecast</strong></p><p>We apply an operational model for the mean drift of small particles near and at the surface. The drift is a sum of the Stokes drift and the current. The Stokes drift is derived from a wave model and the current is calculated by means of a 3D hydrodynamic model.</p><p>In an operational wave model setup (based on WAVEWATCH-III version 7) a parametric tail is supplied as an extension to the prognostic wave spectrum. The parametrisation is based on the modelled spectra level and the first circular moment (the spectral spread) near the highest prognostic frequency, which is typically around 0.5 Hz in operational wave modelling.</p><p>New source terms formulations has been introcuced in wave modelling (e.g. WAVEWATCH-III with effect from 2019) that reproduces the spreading and spectral level well compared to many independent observations.</p><p>The Stokes drift is calculated at a discrete number of depths down to Z = 2/Ks, where Ks is a wave number scale estimated from the prognostic spectrum. The calculation is integrated in the wave model output.</p><p>The application is evaluated in complex weather situations between January 1 and January 6 2020 in the European North West Shelf region. A set of wave model setups are compared with a variation of values of the prognostic spectral cut-off.</p><p>It is demonstrated that a the near-surface drift profile is resolved well with an order of ten discrete depths, and the parametric tail extension requires a low computational time.</p>

SPECTRAL WAVE MODELLING IN TIDAL INLET SEAS: RESULTS FROM THE SBW WADDEN SEA PROJECT

2011 ◽  
Vol 1 (32) ◽  
pp. 44 ◽  
Author(s):  
Ap Van Dongeren ◽  
Andre Van der Westhuysen ◽  
Jacco Groeneweg ◽  
Gerbrant Van Vledder ◽  
Joost Lansen ◽  
...  
Keyword(s):  
Wave Height ◽  
Wave Breaking ◽  
Wadden Sea ◽  
Low Frequency ◽  
Wave Model ◽  
Finite Depth ◽  
Transformation Model ◽  
Wave Transformation ◽  
Sea Waves ◽  
Wave Conditions

Over the last five years a research program has been carried out to assess the performance of the spectral wave model SWAN in the Wadden Sea so that it may be used for the transformation of offshore wave conditions to wave boundary conditions near the sea defenses (dikes and dunes). The assessment was done on the basis of extensive wave measurements conducted in Ameland inlet and the Dutch Eastern Wadden Sea, as well as relevant data from lakes and estuaries. After a first round of assessment, we found that SWAN performed reasonably well for storm conditions but three aspects required further attention. Firstly, focusing on the main channel, SWAN formulations needed to be modified in order to eliminate overprediction of the significant wave height in opposing currents. Secondly, the primary spectral peak of North Sea waves penetrating into the inlet was underpredicted. Best results were obtained when the refraction of low-frequency waves was limited and the bottom friction coefficient was set at a lower value than the current default for wind seas. Thirdly, over the tidal flats the computed ratio of integral wave height over water depth showed an apparent upper limit using the conventional Battjes and Janssen (1978) depth-limited wave breaking formulation, because the wave growth over finite depth is hampered by the present formulation of depth-induced wave breaking. The problem has been solved using a new breaker formulation. All these improvements have lead to a wave transformation model with which reliable wave conditions in the Wadden Sea and related complex areas can be determined.

Sign in / Sign up

Export Citation Format

Share Document