Marine Geophysical Research

Items from 1 to 19 out of 19 results

article

Geologic evolution of the Canarian Islands of Lanzarote, Fuerteventura, Gran Canaria and La Gomera and comparison of landslides at these islands with those at Tenerife, La Palma and El Hierro

J. Acosta, E. Uchupi, A. Muñoz, P. Herranz, more

Marine Geophysical Research > 2003 > 24 > 1-2 > 1-40

In this paper we discuss the results of a swath bathymetric investigation of the Canary archipelago offshore area. These new data indicate that volcanism is pervasive throughout the seafloor in the region, much more that would be suggested by the islands. We have mapped tens of volcanic edifices between Fuerteventura and Gran Canaria and offshore Tenerife, La Gomera, El Hierro and La Palma. Volcanic...

article

Comparison of volcanic rifts on La Palma and El Hierro, Canary Islands and the Island of Hawaii

J. Acosta, E. Uchupi, D. Smith, A. Muñoz, more

Marine Geophysical Research > 2003 > 24 > 1-2 > 59-90

The meso-scale (km) morphology of the well-studied volcanic rift zones on the Island of Hawaii is compared to the morphology of the lesser known rift zones of La Palma and El Hierro, Canary Islands. We find that there are both differences and similarities in their morphologic characteristics. In general, the rift zones on La Palma and El Hierro are shorter (a few tens of km in length) than those on...

article

Salt Diapirs, Salt Brine Seeps, Pockmarks and Surficial Sediment Creep and Slides in the Canary Channel off NW Africa

J. Acosta, E. Uchupi, A. Muñoz, P. Herranz, more

Marine Geophysical Research > 2003 > 24 > 1-2 > 41-57

Circular to elliptical mounds in the Canary Channel with reliefs of 75 to 375 m and diameters of 4 to 8 km partially surrounded by moats with reliefs of 25 to 75 m, were formed by piercement of the seafloor by Mesozoic evaporites. Several long gullies, < 1km wide, with abrupt terminations and pockmarks associated with these mounds were probably eroded by dense brine and hydrocarbon seeps. The salt...

article

Paleoearthquake evidence in Tenerife (Canary Islands) and possible seismotectonic sources

L. I. Gonzalez Vallejo, R. Capote, L. Cabrera, J. M. Insua, more

Marine Geophysical Research > 2003 > 24 > 1-2 > 149-160

A series of clastic dikes and tubular vents were identified in southern Tenerife (Canary Islands). These features are the result of seismic liquefaction of a Holocene sand deposit, as the consequence of a high intensity paleoearthquake. The peak ground acceleration (pga) and magnitude of the paleoearthquake generating these liquefaction features were estimated by back calculation analysis. A representative...

article

Age and composition of the Amanay Seamount, Canary Islands

E. Ancochea, M. J. Huertas

Marine Geophysical Research > 2003 > 24 > 1-2 > 161-169

A number of samples have been dredged from the upper parts of Amanay and El Banquete Seamounts, yet volcanic materials have been collected only on Amanay Seamount. Based on textural features and the presence or absence of kaersutite, two main types of olivine pyroxene basaltic rocks have been identified. The rocks are basanites with high enrichment in the most incompatible elements, similar to that...

article

Gravity analysis offshore the Canary Islands from a systematic survey

A. Carbó, A. Muñoz-Martín, P. Llanes, J. Álvarez, more

Marine Geophysical Research > 2003 > 24 > 1-2 > 113-127

As part of a systematic mapping program of the Hydrographic and Oceanographic Research Plan for the Spanish Exclusive Economic Zone (EEZ), gravity surveys were carried out offshore the Canary Islands. Using the gravity data collected during cruises between 1998 and 2000 aboard the RV Hesperides and satellite and land data, we construct free air and Bouguer anomaly maps and discuss the geodynamic implications...

article

A magnetic anomaly study offshore the Canary Archipelago

M. Catalán, J. Martín Davila, ZEE Working Group

Marine Geophysical Research > 2003 > 24 > 1-2 > 129-148

A scalar magnetic anomaly map of the regions offshore the Canary Archipelago is presented here. This map is based on measurements taken inside the Exclusive Economic Zone Project framework. This paper contains a description of the data set, whose accuracy and internal consistency are analysed. The magnetic anomalies are described and the main structural trends are highlighted. This analysis has served...

article

Morphological and structural analysis in the Anaga offshore massif, Canary Islands: fractures and debris avalanches relationships

P. Llanes, A. Muñoz, A. Muñoz-Martín, J. Acosta, more

Marine Geophysical Research > 2003 > 24 > 1-2 > 91-112

As part of the ‘National Hydrographic and Oceanographic Research Plan for the Spanish Exclusive Economic Zone’, multibeam bathymetry and seismic reflection profiles were obtained in the Canary Islands aboard the R/V Hespérides. The submarine flanks of the Anaga offshore extension of Tenerife Island are here studied to analyze its geomorphology. In the north sector of the Anaga submarine massif, the...

article

Inhomogeneous substrate analysis using EM300 backscatter imagery

Yves Le Gonidec, Geoffroy Lamarche, Ian C. Wright

Marine Geophysical Research > 2003 > 24 > 3-4 > 311-327

Backscatter reflectivity from multibeam echo-sounders provides a powerful tool to efficiently characterize seafloor substrates. A comprehensive EM300 bathymetric and backscatter survey has been completed of Cook Strait, in central New Zealand. This paper presents a detailed analysis of the realtime corrections applied to the raw EM300 multibeam data and additional corrections required to compute angular...

article

Book review

C. Ebinger

Marine Geophysical Research > 2003 > 24 > 3-4 > 361-362

article

Structure of Mesozoic oceanic crust in the vicinity of the Cape Verde Islands from seismic reflection profiles

M. Y. Ali, A. B. Watts, I. Hi1l

Marine Geophysical Research > 2003 > 24 > 3-4 > 329-343

Multichannel seismic reflection profile data have been used to determine the internal structure of Mesozoic oceanic crust in the vicinity of the Cape Verde islands. The data show the oceanic crust to be characterized by both dipping and sub-horizontal reflectors. Several lines of evidence argue against the reflectors being scattering artifacts arising, for example, from rough basement topography....

article

Structural patterns and tectonic history of the Bauer microplate, Eastern Tropical Pacific

Barry W. Eakins, Peter F. Lonsdale

Marine Geophysical Research > 2003 > 24 > 3-4 > 171-205

The Bauer microplate was an independent slab of oceanic lithosphere that from 17 Ma to 6 Ma grew from 1.4 × 10⁵ km² to 1.2 × 10⁶ km² between the rapidly diverging Pacific and Nazca plates. Growth was by accretion at the lengthening and overlapping axes of the (Bauer-Nazca) Galapagos Rise (GR) and the (Pacific-Bauer) East Pacific Rise (EPR). EPR and GR axial propagation to create and rapidly grow the...

article

A topographic surface reduction of aeromagnetic anomaly field over the Tyrrhenian sea area (Italy)

O. Faggioni, F. Caratori. Tontini, P. Stefanelli, C. Carmisciano, more

Marine Geophysical Research > 2003 > 24 > 3-4 > 265-277

This paper shows the results of a detailed reprocessing of aeromagnetic data, obtained by the downward projection to the seabed. The area of interest is centered over the Tyrrhenian Basin, whose bathymetric–topographic lay-out is characterized by a somewhat irregular trend. The origin of the intense depth variations depends on the Tyrrhenian structural setting, that is associated with the presence...

article

The Ionian Abyssal Plain (central Mediterranean Sea): Morphology, subbottom structures and geodynamic history – an inventory

W. Hieke, H. B. Hirschleber, G. A. Dehghani

Marine Geophysical Research > 2003 > 24 > 3-4 > 279-310

In order to understand the structure and evolution of the Mediterranean Ridge accretionary complex, it is necessary to understand the structure and history of its foreland. The Ionian Abyssal Plain is one of the varying types of foreland. The state of knowledge for that is presented. Its contour and detailed relief are described for the first time. Based on published and hitherto unpublished seismic...

article

Analysis of the magnetic anomaly field of the volcanic district of the Bay of Naples, Italy

M. Secomandi, V. Paoletti, G. Aiello, M. Fedi, more

Marine Geophysical Research > 2003 > 24 > 3-4 > 207-221

We here present and discuss the results of the analysis and qualitative interpretation of two magnetic surveys performed in the Bay of Naples in 1998 and 2000. A map of the Bay of Naples based on the data acquired during these surveys has already been published by the Italian CNR-IAMC Research Institute. We re-processed the same data to produce maps of the pole reduced, analytic signal and horizontal...

article

Book review

Ian Wright

Marine Geophysical Research > 2003 > 24 > 3-4 > 359-360

article

New, high resolution swath bathymetry of Gettysburg and Ormonde Seamounts (Gorringe Bank, eastern Atlantic) and first geological results

G. De. Alteriis, S. Passaro, R. Tonielli

Marine Geophysical Research > 2003 > 24 > 3-4 > 223-244

High resolution swath bathymetry of shallow water (< 200 m) oceanic seamounts is a relatively rare issue. During the recent Gorringe_2003 cruise over the Gorringe Bank (Eastern Atlantic) we collected multibeam bathymetry on the bank’s two shallow summits, Gettysburg and Ormonde in the –25/–400m depth range at a resolution rarely achieved over an oceanic seamount. We also carried out bottom samplings...

article

Heat flux estimate of warm water flow in a low-temperature diffuse flow site, southern East Pacific Rise 17°25′ S

Shusaku Goto, Masataka Kinoshita, Kyohiko Mitsuzawa

Marine Geophysical Research > 2003 > 24 > 3-4 > 345-357

A low-temperature diffuse flow site associated with abundant vent fauna was found by submersible observations on the southern East Pacific Rise at 17°25′ S in 1997. This site was characterized by thin sediment covered pillow and sheet lavas with collapsed pits up to ∼15 m in diameter. There were three warm water vents (temperature: 6.5 to 10.5 °C) within the site above which the vented fluids rise...

article

Abrupt axial variations along the slow to ultra-slow spreading centers of the northern North Fiji Basin (SW Pacific): Evidence for short wave heterogeneities in a back-arc mantle

Erwan Garel, Yves Lagabrielle, Bernard Pelletier

Marine Geophysical Research > 2003 > 24 > 3-4 > 245-263

This study presents results of surveys conducted along the slow to ultra-slow spreading axis of the Northern North Fiji Basin (NNFB), including the Hazel Holmes, Tripartite and South Pandora Ridges, and the newly discovered Futuna and North Cikobia spreading centers. Spreading segments along these axes display highly contrasted axial morphologies, ranging from a rift valley to a prominent axial high...

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2003

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Keywords

CANARY ISLANDS (5)
MULTIBEAM MAPPING (2)
ACOUSTIC BACKSCATTER (1)
AMANAY SEAMOUNT (1)
ANAGA MASSIF (1)
ANNEXATION (1)
AVALANCHES (1)
AXIAL MORPHOLOGY (1)
BACKARC SPREADING RIDGES (1)
BACKSCATTER (1)
BATHYMETRY (1)
BAUER MICROPLATE (1)
BAY OF NAPLES (1)
BOUGUER ANOMALY (1)
CANARY CHANNEL (1)
CANARY ISLAND (1)
CAPE VERDE ISLANDS (1)
COOK STRAIT (1)
DEBRIS AVALANCHE (1)
DOWNWARD CONTINUATION (1)
EAST PACIFIC RISE (1)
EASTERN CANARIAN VOLCANIC RIDGE (1)
EM300 (1)
FLEXURE (1)
FLUID SEEPAGE (1)
FRACTURE ZONES (1)
FRACTURES (1)
FREE AIR ANOMALY (1)
GALAPAGOS RISE (1)
GEODYNAMICS (1)
GEOMAGNETISM (1)
GEOMORPHOLOGY (1)
GETTYSBURG SEAMOUNT (1)
GORRINGE BANK (1)
GRADIENT ZONE (1)
GRAVITY FIELD (1)
HAWAII (1)
HEAT FLUX (1)
HIGH RESOLUTION BATHYMETRY (1)
HYDROTHERMAL PLUME (1)
IONIAN ABYSSAL PLAIN (1)
K-AR GEOCHRONOLOGY (1)
LA PALMA AND EL HIERRO (1)
LONG-TERM MONITORING (1)
MAGMATO-TECTONIC PROCESSES (1)
MAGNETIC FIELD (1)
MANTLE DIAPIR (1)
MARINE GEOMAGNETISM (1)
MARINE GRAVITY (1)
MARINE MAGNETIC ANOMALIES (1)
MEDITERRANEAN RIDGE ACCRETIONARY COMPLEX (1)
MESSINIAN EVAPORITES (1)
MICROPLATE KINEMATICS (1)
MOHO (1)
MOUNDS (1)
MULTIBEAM (1)
MULTIBEAM BATHYMETRY (1)
NORTH FIJI BASIN (1)
OCEANIC CRUST (1)
OCEANIC ISLAND BASALTS (1)
ORMONDE SEAMOUNT (1)
PALEOLIQUEFACTION (1)
PALEOSISMICITY (1)
PHLEGREAN OFFSHORE (1)
PLATE RECONSTRUCTIONS (1)
POTENTIAL METHODS (1)
REFLECTIVITY (1)
RIFTING (1)
SALT DIAPIRISM (1)
SEAFLOOR CHARACTERIZATION (1)
SEISMIC REFLECTORS (1)
SEISMITES (1)
SEISMOTECTONIC (1)
SOUTHERN EAST PACIFIC RISE (1)
SUBSTRATE (1)
SWATH-BATHYMETRY (1)
TENERIFE (1)
TENERIFE ISLAND (1)
TENSIONAL TECTONICS (1)
THINNED CONTINENTAL CRUST (1)
TYRRHENIAN SEA (1)
UNDERPLATING (1)
VERTICAL ACCRETION (1)
VESUVIUS OFFSHORE (1)
VOLCANIC RIFTS (1)
WARM WATER FLOW (1)
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