Canary Island Volcano Monitoring Program
a) Consejo Superior de Investigaciones Cientificas (CSIC): (Research)
(1) Departamento de Volcanologia
Museo Nacional de Ciencias Naturales (CSIC)
Jose Gutierrez Abascal 2
E-28006 Madrid, Spain
Telefax: (34) 91- 5644740
Leader: Ramon Ortiz
(2) Departament de Geofisica i Geo-Riscs
C/ Lluol Sabar/n
E-08028 Barcelona, Spain
Telefax: (34) 93 411 00 12
Leader: Joan Marti
b) Instituto Geografico Nacional (IGN): (Monitoring)
(3) Seccie Volcanologia
Observatorio de Madrid
C/ Alfonso XII, nº 3.
E-28014, Madrid, Spain
Telefax: (34) 915271935
Leader: Carmen Lopez
(4) Centro Geofisico de Canarias
c/ La Marina, Edificio Multiple
E-38001 Santa Cruz de Tenerife, Spain
Leader: Maria Jose Blanco
Scientist in charge:
Dra. Maria Jose Blanco - Seismology (4)
Dra. Alicia Felpeto - Volcanology (3)
Dra. Alicia Garcia - Geophysics (1)
Grad. Carmen Lopez - Seismology (3)
Dr. Joan Marti - Volcanology (2)
Dr. Ramon Ortiz - Geophysics (1)
The Canarian Archipelago belongs to the oceanic islands group and with the other Atlantic archipelagos as Azores, Madeira, Salvages and Cabo Verde configure the Macaronesia islands group. The duration of the volcanic activity in the archipelago (more than 50 Ma) and the implicated volumes (150.000 km3) are the main characteristics of the Canarian volcanism, which looks inconsistent to its geodynamic location over a passive continental margin. Furthermore, the present volcano tectonic alignments coincide to the prolongation of the African Atlas faults and/or the Atlantic transform faults system along the basement.
The Canarian volcanism shows high complexity not only in the products nature, but also in the eruptive mechanism that can be divided into two groups: Effusive basaltic volcanism and Explosive felsic volcanism. The monogenic basaltic eruptions are relatively calm, in exception those appearing on the coast, where the explosivity increases with the interaction of water and magma (hydromagmatic eruptions), forming low and wide craters. Phonolitic Plinian eruptions are the origin of the spread thick pumice deposits in the south of the Island that correspond to big ignimbrite bodies. The last explosive dated eruption corresponds to Montalanca, located on the base of Teide stratovolcano, 2000 years ago.
In the last five hundred years (historical period for Canary Islands) the return time for basaltic eruptions is approximately 30 years for the archipelago and 90 for Tenerife Is. The mayor eruptive event (in historical period) was 1730-36 Timanfaya basaltic eruption (?1km3).
In Tenerife, is remarkable the presence of the Teide-Pico Viejo stratovolcanoes (3718 m over sea level, being the highest structure in the Atlantic Ocean, and the third-highest volcanic complex on Earth rising almost 7000 m from the surrounding seafloor) and the Las Cas collapse caldera (showing 16 km x 9 km axis).
Apart of the scientific interest, the Canarian volcanism represents a potential risk for more than two million of people as inhabitants as tourists of its seven islands. This circumstance implies the necessity of a continuous volcanic activity vigilance and development of preventive protocols in case of volcanic crises. According to the USGS OPEN-FILE REPORT 2005-1164, Teide volcano must be included into the very high threat group.
From 2004 the Spanish Geographic Institute is officially responsible on volcanic alerts and the Active Volcanism research team of CSIC acts as its Scientific Assessor. Both institutions (IGN and CSIC) have named a Scientific Commission for evaluating and monitoring the volcanic phenomena in Spain operating from 2007 and integrating the Scientists in charge above mentioned.
Following more than 30 years of seismic and volcanic quiescence, from 2000 the Canary Islands region started to show an increase of regional seismic activity. In spring 2004, there was a significant increase in the number of seismic events located inland on Tenerife Island, especially around the Cas Caldera and the North West flanks of Teide Volcano. Volcano-tectonic events, tremors and long-period signals have been identified. The increase of activity in 2004 coincided with other signs (an increase of fumarolic activity at the Teide volcano on Tenerife Island, an increase in the emission of carbon dioxide in the north-western part of the island, and changes in the gravimetric field on the northern flank of the volcano) and, after several seismic events felt by the population, the first alert level was declared by the civil protection division of the local government. At present, the seismic energy rate and the Richter b constant for the activity around Teide volcano, and the presence of volcanic tremor indicate a magmatic process in course.
Volcano monitoring results:
. Seismicity associated with volcanic systems in Tenerife Is. from 2004. The analysis of the seismic noise signal shows the existence of volcanic tremors sometimes with memory of 3-4 days and forecasting signs in both volcanic and tectono-volcanic events.
. The deformation models of Tenerife Is. show that some areas have been affected by the 2004 seismovolcanic crisis.
Under these conditions, a reawakening of central volcanic system of Tenerife Is. could be considered. For the other islands there is not an area showing a higher eruption probability in a medium term.
Canary Island Volcano Surveillance Program
. IGN Permanent Regional Geophysical Network. Details and real time data are available on: http://www.ign.es/ign/es/IGN/volcanologia.jsp
. CSIC Geophysical Instruments and networks (according to the research projects in course).