Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Satellite methods for monitoring volcanic activity in the Andes Cordillera

08.10.2007
The central part of the Andes situated between southern Peru and Chile bears 50 active or potentially volcanoes, spread along a 1500 km-long arc. These volcanic structures mostly rise to between 4000 and 7000 m, are very remote with abrupt slopes and are often cloaked in snow.

Few studies have been made on them as such conditions make field surveying extremely difficult. A team of IRD researchers working in partnership with the University of Chile (Santiago) and the Observatoire de Physique du Globe of Clermont-Ferrand (1) focused special attention on the Lastarria-Cordon del Azufre volcanic complex. With a surface area of 1600 km², it is situated in the central Andes Cordillera at the border between Argentina and Chile near Antofagasta.

Research projects on deformations of the earth crust, conducted in this region between 1992 and 2000 by a North American team, had led to the detection of a long wavelength signal over the area’s topography, extracted from analysis of data collected by the European Space Agency (ESA) satellite ERS-1. This deformation would correspond to crustal inflation affecting the whole Lastarria-Cordon del Azufre complex. Although this volcano is not considered as active, as the last eruption dates back 9000 years, such inflation could express an underlying activity related to the dynamics of a functioning magma chamber.

IRD geophysicists continued such investigations on the deformations at work in the Lastarria-Cordon del Azufre complex in 2003, by using radar interferometry. This measurement method is based on the superimposition of two satellite radar images of the same geographical area taken at different times. The resulting differential signal between the images, termed the interferogram, provides a way of detecting possible deformation of the earth crust. The value of the wavelength associated with it is proportional to the depth of the source of deformation, down in the lithosphere. For this study, the scientists made use of data acquired by ENVISAT, a satellite ESA launched in 2002. Its ASAR (Advanced Synthetic Aperture Radar) sensor enables it, like its predecessors ERS-l, ERS-2, to perform radar imagery in any weathers. This attribute proves particularly useful for surveillance of the mountainous regions of Latin America.

Between March 2003 and June 2005, ENVISAT recorded a time-series of eight images of the Lastarria-Cordon del Azufre volcanic complex. The IRD team used special software to process the images and obtained 28 interferograms. This data set led to measurement of inflation of about a centimetre affecting the crust over the whole of the area studied . As in the North American study, a long wavelength regional-scale signal was found, covering a surface area of about 45 km long by 35 km wide corresponding to the entire volcanic complex. A short wavelength signal not previously identified was also revealed, but unlike the first, it was located at the smaller scale of the Lastarria volcano only.

Two distinct hypotheses are envisaged to explain the emission of these two wavelengths. As the inflation measured at regional scale corresponds to a long wavelength signal, it has a fairly deep source, estimated by the geophysicists at between 7 and 15 km down. An inflation located at such a depth is highly likely to be generated by magmatic activity. The source of the short wavelength signal, located at about 1000 m beneath the summit of the Lastarria volcano, is more uncertain, however. Indications nevertheless suggest a link with the circulation of hydrothermal fluids.

Future forecasting of the possible evolution of the Lastarria-Cordon del Azufre volcanic complex requires the acquisition of field data to complement the satellite data obtained. GPS measurements especially will enable researchers to check if these inflation effects measured using satellite data effectively correspond to movements of the earth crust. The hope is to obtain further information on changes of mass or density at depth using gravimetry, a geophysical method used for detecting the spatial and temporal variations of the gravity field. Thus, a modification of gravity combined with a displacement of the terrestrial crust could indicate a filling or an emptying of a magma chamber and therefore confirm an underlying volcanic activity. If this turned out to be true, the Lastatria-Cordon del Azufre volcanic complex would be the only area under the Andes where the formation of large magma reservoirs has been demonstrated. In the future, such observation methods could be applied to studying volcanic activity in many regions, like the Andean Cordillera, where access is difficult and thus make the surveillance of volcanic structures as effective as possible.

Grégory Fléchet - DIC :
(1) This research was conducted in partnership with several laboratories in France (Institut de Physique du Globe de Paris, Université de Clermont-Ferrand, Université de Toulouse, Université de Savoie), in Chile (Universidad de Chile, Sernageomin), Ecuador (Escuela Politecnica Nacional) and Peru (Instituto Geofisico del Perú, Conida).

Grégory Fléchet | alfa
Further information:
http://www.ird.fr/fr/actualites/fiches/2007/fas275.pdf

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Smallest transistor worldwide switches current with a single atom in solid electrolyte

17.08.2018 | Physics and Astronomy

Robots as Tools and Partners in Rehabilitation

17.08.2018 | Information Technology

Climate Impact Research in Hannover: Small Plants against Large Waves

17.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>