K-Ar ages and magnetic stratigraphy of a hotspot-induced, fast grown oceanic island: El Hierro, Canary Islands

Guillou, Hervé; Carracedo, Juan Carlos; Torrado, Francisco José Pérèz; Badiola, Eduardo Rodríguez

doi:10.1016/0377-0273(96)00021-2

Cited by 259 publications

(274 citation statements)

References 25 publications

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“…El Hierro, the youngest of the Canary Islands (oldest subaerial rocks dated at 422 1.12 Ma), is situated at the southwestern corner of the archipelago and rises from 4,000 423 m depth to an altitude of about 1,500 m a.s.l (Guillou et al 1996). The island was 424 formed by the consecutive growth of two volcanic edifices, Tiñor volcano in the NE and 425…”

Section: El Hierro Island 420 421mentioning

confidence: 99%

Evaluating Topographic Effects on Ground Deformation: Insights from Finite Element Modeling

2015

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14 15Ground deformation has been demonstrated to be one of the most common signals of 16 volcanic unrest. Although volcanoes are commonly associated with significant 17 topographic relief, most analytical models assume the Earth's surface as flat. However, 18 it has been confirmed that this approximation can lead to important misinterpretations 19 of the recorded surface deformation data. Here we perform a systematic and quantitative 20 analysis of how topography may influence ground deformation signals generated by a 21 spherical pressure source embedded in an elastic homogeneous media and how these 22 variations correlate with the different topographic parameters characterizing the terrain 23 form (e.g. slope, aspect, curvature, etc.). For this, we bring together the results exposed 24 in previous published papers and complement them with new axisymmetric and 3D 25Finite Elements (FE) models results. First, we study, in a parametric way, the influence 26 of a volcanic edifice centered above the pressure source axis. Second, we carry out new 27 3D FE models simulating the real topography of three different volcanic areas 28 representative of topographic scenarios common in volcanic regions: Rabaul caldera 29 (Papua New Guinea) and the volcanic islands of Tenerife and El Hierro (Canary 30Islands). The calculated differences are then correlated with a series of topographic 31 parameters. The final aim is to investigate the artifacts that might arise from the use of 32 half-space models at volcanic areas due to diverse topographic features (e.g. collapse 33 caldera structures, prominent central edifices, large landslide scars, etc.). 34 35

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Section: El Hierro Island 420 421mentioning

confidence: 99%

Evaluating Topographic Effects on Ground Deformation: Insights from Finite Element Modeling

2015

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“…They originated as a result of an intraplate magmatic episode lasting over 40 Ma [Araña and Ortiz, 1991] that gave rise to Holocene volcanism on all of these islands. El Hierro is a composite shield structure created by a combination of different volcanic edifices, which rises from 4000 m below sea level (bsl) to a maximum altitude of 1501 m above sea level (asl) and has a surface area of about 279 km 2 [Guillou et al, 1996;Carracedo et al, 2001]. The onshore geology of El Hierro shows three giant lateral collapses, namely, Las Playas, El Julan, and El Golfo (Figure 1), and the San Andrés fault (on the NE flank of the island) that could correspond to an aborted lateral collapse [Day et al, 1997].…”

Section: Background Information On the Geology Of El Hierro And The 2mentioning

confidence: 99%

Volcanic signatures in time gravity variations during the volcanic unrest on El Hierro (Canary Islands)

et al. 2014

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Gravity changes occurring during the initial stage of the 2011-2012 El Hierro submarine eruption are interpreted in terms of the preeruptive signatures during the episode of unrest. Continuous gravity measurements were made at two sites on the island using the relative spring gravimeter LaCoste and Romberg gPhone-054. On 15 September 2011, an observed gravity decrease of 45 μGal, associated with the southward migration of seismic epicenters, is consistent with a lateral magma migration that occurred beneath the volcanic edifice, an apparently clear precursor of the eruption that took place 25 days later on 10 October 2011. High-frequency gravity signals also appeared on 6-11 October 2011, pointing to an occurring interaction between a magmatic intrusion and the ocean floor. These important gravity changes, with amplitudes varying from 10 to À90 μGal, during the first 3 days following the onset of the eruption are consistent with the northward migration of the eruptive focus along an active eruptive fissure. An apparent correlation of gravity variations with body tide vertical strain was also noted, which could indicate that concurrent tidal triggering occurred during the initial stage of the eruption.

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“…The origin of the steep escarpments bounding the seawardfacing embayment in the Canaries has been the subject of different interpretations, since its first association with gravitational processes by Bravo (1952). Nowadays it is accepted that giant landslides are a common feature in the Canary Islands and the relation between giant landslides and straight-walled valleys, calderas and wide coastal embayments, has been found onshore (Ancochea et al, 1990;Ancochea et al, 1994;Carracedo 1994;Guillou et al, 1996) and offshore (Watts and Masson, 1995;Teide Group, 1997;Masson, 1996;Urgeles et al, 1997;Carracedo, 1999Mitchell et al, 2003, Masson et al, 2002 andAcosta et al, this issue). In Figure 7 the geographical position of the onshore Güimar's Valley scarp has been plotted, as well as the trace of the scarp found offshore.…”

Section: South Sectormentioning

confidence: 98%

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

Llanes

Muñoz²,

Muñoz-Martı́n

et al. 2003

Mar Geophys Res

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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 extension of the Anaga Debris Avalanche has been mapped for the first time, and a volume of 36 km 3 was calculated. The relationship between the Anaga and Orotava Debris Avalanches is also described. Faulting has been recognized as a key process for the occurrence of debris avalanches and the growth of volcanic lineaments. Moreover, faulting affects previous structures and the channelling of debris flows. Structural analysis shows the typical radial pattern of an oceanic island. In addition, a NE-SW dominant direction of faulting was obtained, consistent with the Tenerife Island structural trend seen in the Anaga Massif and Cordillera Dorsal. NW-SE and E-W are two other main trends seen in the area. Special interest is manifest in two long faults: 'Santa Cruz Fault' bounds the southern edge of Anaga offshore Massif with a length of 50 km and a direction that changes from NE-SW to almost E-W. The Güimar Debris Avalanche was probably channeled by this fault. The 'Guayotá Fault' was recognized in several seismic profiles with a N-S direction that changes towards NW-SE at its southern end. This fault affects the more recent sediments with a vertical offset of 25-30 m, along 60 km. It has been interpreted as a transpressive strike-slip fault.

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K-Ar ages and magnetic stratigraphy of a hotspot-induced, fast grown oceanic island: El Hierro, Canary Islands

Cited by 259 publications

References 25 publications

Evaluating Topographic Effects on Ground Deformation: Insights from Finite Element Modeling

Evaluating Topographic Effects on Ground Deformation: Insights from Finite Element Modeling

Volcanic signatures in time gravity variations during the volcanic unrest on El Hierro (Canary Islands)

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

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