Sea-Bottom Reverberation: The Role of Volume Inhomogeneities of the Sediment

1993 ◽  
pp. 59-64 ◽  
Author(s):  
M. Gensane
Keyword(s):  
Sea Bottom

How fluids impact seismic/aseismic slip in the Ecuadorian subduction zone? The HIPER marine project

2021 ◽  
Author(s):  
Audrey Galve ◽  
Andreas Rietbrock ◽  
Philippe Charvis ◽  
Giorgio De la Torre ◽  
Sandro Vaca ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Seismic Activity ◽  
Waveform Inversion ◽  
Geodetic Network ◽  
Structural Heterogeneity ◽  
Rupture Zone ◽  
Aseismic Slip ◽  
Health Crisis ◽  
Sea Bottom

<p>Identifying the circulation of fluids in subduction zone system and understanding their role on the megathrust fault slip modes remains one of the outstanding challenges in Earth Sciences. As these faults have the capacity to generate mega-earthquakes, the associated hazard to the society is significant.</p><p>The Ecuadorian subduction zone is one of the places in the world where very large earthquakes can occur, as shown by the Mw 8.8 earthquake in 1906. In April 2016, a Mw 7.8 earthquake broke the southern part of the 1906 earthquake rupture zone, causing hundreds of deaths and millions of dollars in damages along an increasingly populated coastline. The seismological and geodetic network in place since several years and a dense post-seismic deployment, contributed to observe and define the rupture zone and areas affected by aseismic slip on the shallowest portion of the megathrust fault. Those hints of transient slip behaviors, for which fluids have been invoked to explain their occurrence, bring Ecuador to the forefront of natural laboratories to study the link between fluids and slip mode.</p><p>The HIPER marine campaign in March/April 2020 on board R/V Atalante was designed to acquire a dense active/passive, 2D/3D, onshore/offshore dataset, and in particular to derive the role of fluids in slip modes on the Ecuadorian margin. Thanks to an international consortium (Ecuador, Germany, France, United States) we had access to a large number of OBS (47) and land stations (~700) to record both R/V Atalante’s shots and the seismic activity.</p><p>The large-N experiment allowed a high density onshore/offshore deployment to perform shots and earthquakes FWI (Full Waveform Inversion) and obtain sufficient resolution to tackle the role of fluids with respect to interplate roughness, the nature of sediments, upper plate and lower plate’s structural heterogeneity in seismic/aseismic slip behavior.</p><p>A few days after starting the marine campaign, countries closed their frontiers due to the Covid-19 health crisis. The HIPER marine campaign was stopped and scientists on board were repatriated home. During the 10 days out of the 42 days planned, we managed to acquire the planed multichannel seismic reflection lines (abstract by L. Schenini - TS12.1). However, we collected only one of the three planned OBS wide-angle seismic lines (abstract by A. Skrubej - GD4.3), and no OBSs have been deployed for seismic activity monitoring.</p><p>The unique joint reflection/refraction line is perpendicular to the trench, sampling the megathrust fault where aseismic slip occurs, north of Pedernales. On our tomographic inversion, iso-velocity contours characterizing the oceanic crust entering the subduction, are downwards deflected 15 km before the trench. Such observation could be related to fluids affecting the crust and the upper mantle. On MCS image, we observe within the trench a rough oceanic basement, with a horst-like topographic high which outcrops at sea-bottom. Such structure could facilitate fluids infiltrating the crust before the trench in addition to bending faults, and possibly explain low Vp anomaly obtained on our coincident tomographic image.</p><p>A new marine campaign HIPER 2.0 is rescheduled in March/April 2022 to acquire the missing data.</p>

scholarly journals Revisiting the Role of Convective Deep Water Formation in Northern Baltic Sea Bottom Water Renewal

2020 ◽  
Vol 125 (10) ◽  
Author(s):  
Céline Giesse ◽  
H. E. Markus Meier ◽  
Thomas Neumann ◽  
Matthias Moros
Keyword(s):  
Baltic Sea ◽  
Deep Water ◽  
Bottom Water ◽  
Deep Water Formation ◽  
Water Renewal ◽  
Sea Bottom ◽  
Water Formation

scholarly journals Литогенный фактор в формировании и распространении донных биоценозов (Апшеронский архипелаг, Каспийское море)

2020 ◽  
Vol 12 (3) ◽  
pp. 61
Author(s):  
К.М. Петров
Keyword(s):  
Caspian Sea ◽  
The Caspian Sea ◽  
Leading Role ◽  
Basement Rocks ◽  
Sea Bottom

The results of decades of comprehensive investigations of the undersea grounds of the Absheron Archipelago (the Caspian Sea), including landscape and bionomic zoning, which started in 1960ies, are overviewed. The five main types of undersea grounds and associated biocenoses are characterized with special attention to bivalve tanathocenoses associated with naked basement rocks. Based on these analyses, the leading role of geologic and geomorphologic structure of sea bottom in the development and distribution of natural complexes and biocenoses of sea bottom is suggested.

Protection effects on Mediterranean fish assemblages associated with different rocky habitats

2012 ◽  
Vol 93 (2) ◽  
pp. 425-435 ◽  
Author(s):  
Rita Sahyoun ◽  
Simona Bussotti ◽  
Antonio Di Franco ◽  
Augusto Navone ◽  
Pieraugusto Panzalis ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Marine Protected Area ◽  
Economic Value ◽  
Economic Role ◽  
North East ◽  
Rocky Reefs ◽  
Sea Bottom ◽  
Total Fish ◽  
Rocky Habitats

Rocky banks (i.e. sea mountain-like structures rising from the sea bottom) are hard substrate habitats of high socio-economic value (e.g. for fishermen and divers) and ecological relevance as they often host unusually high density of fish. Here we tested whether the response of fish assemblages to protection (i.e. related to the presence of a Marine Protected Area (MPA)) in rocky banks is comparable with the response of rocky reefs dropping from the coast (hereafter called ‘coastal rocky substrates’), and whether there are differences between fish assemblages associated with protected and unprotected rocky banks. Fish assemblages were assessed in shallow and deep coastal rocky substrates, and in rocky banks, in unprotected and protected conditions at a Mediterranean MPA in north-east Sardinia in August 2007 and 2008. Whole fish assemblage structures (in terms of biomass) differed between protected and unprotected conditions in both study years. Fish assemblages at rocky banks, in addition, differed from those associated with coastal rocky substrates. Total fish biomass (summing contribution of all species) was higher under protected than unprotected condition in 2007, while species richness and total fish density did not demonstrate any significant change related to protection. The responses to protection displayed by the target species Epinephelus marginatus and Diplodus sargus were clear especially in terms of greater frequency of large-sized specimens in both study years. Biomass of E. marginatus in 2007 and density of D. sargus in 2007 and 2008 were significantly higher in protected than unprotected conditions, especially in protected rocky banks. This study emphasizes the ecological and socio-economic role of protection and the potential role of rocky banks within management/conservation programmes in the Mediterranean Sea.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management

The power of norms to sway fused group members

2018 ◽  
Vol 41 ◽  
Author(s):  
Winnifred R. Louis ◽  
Craig McGarty ◽  
Emma F. Thomas ◽  
Catherine E. Amiot ◽  
Fathali M. Moghaddam
Keyword(s):  
Evolutionary Anthropology ◽  
Normative Systems ◽  
Violent Extremism ◽  
Identity Fusion ◽  
Group Members

AbstractWhitehouse adapts insights from evolutionary anthropology to interpret extreme self-sacrifice through the concept of identity fusion. The model neglects the role of normative systems in shaping behaviors, especially in relation to violent extremism. In peaceful groups, increasing fusion will actually decrease extremism. Groups collectively appraise threats and opportunities, actively debate action options, and rarely choose violence toward self or others.

Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux
Keyword(s):  
Decision Making ◽  
Individual Differences ◽  
Cognitive Processes ◽  
Evolutionary History ◽  
Behavioral Responses ◽  
History Of ◽  
Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

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