Papers by Servando De La Cruz-reyna
Geophysical Monograph Series, 2000
Résumé/Abstract Direct satellite data reception at high temporal frequencies and automated proces... more Résumé/Abstract Direct satellite data reception at high temporal frequencies and automated processing enable near-real-time, near-continuous thermal monitoring of volcanoes. We review what has been achieved in terms of turning this capability into real-time tools of use ...
In July 2011 at El Hierro (Canary Islands, Spain), a volcanic unrest was detected, with significa... more In July 2011 at El Hierro (Canary Islands, Spain), a volcanic unrest was detected, with significant deformations followed by increased seismicity. A submarine eruption started on 10 October 2011 and ceased on 5 March 2012, after the volcanic tremor signals persistently weakened through February 2012. However, the seismic activity did not end when the eruption, as several other seismic crises followed since. The seismic episodes presented a characteristic pattern: over a few days the number and magnitude of seismic event increased persistently, culminating in seismic events severe enough to be felt all over the island. In all cases the seismic activity was preceded by significant deformations measured on the island’s surface that continued during the whole episode. Analysis of the available GNSS-GPS and seismic data suggests that several magma injection processes occurred at depth from the beginning of the unrest. A model combining the geometry of the magma injection process and the ...
From the July 19, 2011 an increase of seismicity, accompanied by a remarkable process of deformat... more From the July 19, 2011 an increase of seismicity, accompanied by a remarkable process of deformation, was detected on the island of El Hierro. This reactivation process, instrumental and scientifically monitored, culminates in the occurrence of a submarine eruption, with the emergence of a strong tremor signal, in the south of the island on October 10, 2011. Both processes (unrest and eruption) have different phases and behaviors clearly evidenced by the deformation and seismicity. This work is the result of an exhaustive analysis of seismic signals from three stations deployed on the island of El Hierro(CTAB and CTIG (IGN) and REST (CSIC)), in order to explain the behavior of the volcanic system responsible for the submarine eruption of Las Calmas sea and its evolution, as well as evidence of a second submarine eruption in the north of the island (ElGolfo). The spectral content of signals from the seismic stations in the north of the island (CTIG and CTAB) and the area around the e...
Bulletin of Volcanology, 2001
Some volcanoes exhibit at times accelerating strain and seismicity before eruptions. Different au... more Some volcanoes exhibit at times accelerating strain and seismicity before eruptions. Different authors have used this behavior to predict eruptions and to develop materials-science models. Here, a linear Kelvin-Voigt viscoelastic model is proposed to describe the observed behavior. This model also has applications to other failure phenomena, such as landslides. The strain rate of a variety of materials under constant stress after an instantaneous elastic response is found to be well described by a general relaxation law:
Journal of Volcanology and Geothermal Research, 1984
Casadevall, T.removed 0.2 km 3 of rock to form a 1-km-wide 300-m-deep summit crater. By late Apri... more Casadevall, T.removed 0.2 km 3 of rock to form a 1-km-wide 300-m-deep summit crater. By late April 1982 a lake had begun to form on the crater floor, and by November 1982 it attained a maximum surface area of 1.4 × l0 s m: and a volume of 5 × 104 m 3. Accumulation of 4--5 m of rainfall between July and October 1982 largely formed the lake. In January 1983, temperatures of fumaroles on the crater floor and lower crater walls ranged from 98 to 115°C; by October 1983 the maximum temperature of fumarole emissions was 99°C. In January 1983 fumarole gas emissions were greater than 99 vol. % H20 with traces of COs, SO2, and H2S. The water of the lake was a hot (T = 52--58°C), acidic (pH = 0.5), dilute solution (34,046 mg L -1 dissolved solids; C1/S = 20.5). Sediment from the lake contains the same silicate minerals as the rocks of the 1982 pyroclastic deposits, together with less than 1% of elemental sulfur. The composition and temperature of the lake water is attributed to: (1)solution of fumarole emissions; (2) reaction of lake water with hot rocks beneath the lake level; (3) sediments washed into the lake from the crater walls; (4) hydrothermal fluids leaching sediments and formational waters in sedimentary rocks of the basement; (5) evaporation; and (6) precipitation.
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Papers by Servando De La Cruz-reyna