Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Renewed volcanic activity at the Phlegrean Fields tracked by Envisat

23.08.2006
Satellite images acquired by ESA’s Envisat satellite have revealed the volcanic region of the Phlegrean Fields, located in southern Italy near the city of Naples, has entered a new uplift phase.

Using Differential SAR Interferometry (DInSAR), scientists at the Institute for the Electromagnetic Sensing of the Environment (IREA) of the Italian National Research Council (CNR) mapped the changes in the caldera – a ring-shaped region which includes several volcanoes – and discovered the area has uplifted about 2.8 centimetres from 2005 to 2006.

DInSAR, a sophisticated version of 'spot the difference', involves mathematically combining different satellite radar images, acquired from as near as possible to the same point in space at different times, to create digital elevation models and reveal otherwise undetectable changes occurring between image acquisitions.

With a diameter of 13 kilometres, the Phlegrean Fields caldera had its last eruption back in 1538 but has exhibited signs of unrest (bradyseismic activity) in recent years. Its underlying magma system remains active, leading to rapid periods of ground uplift followed by longer-term subsidence. The most recent uplift event occurred between March and August 2000.
The satellite images used to detect the newest uplift phase of the Phlegrean Fields, known in Italy as Campi Flegrei, were acquired from January 2005 to April 2006 and show an area of maximum deformation localised in the centre of the town of Pozzuoli, which lies near the caldera’s centre, with the deformation extending westward to the area surrounding Monte Nuovo. By using the data, scientists were also able to determine the uplift trend started in June 2005.

Ground deformation is recorded as part of the phenomena which precedes a volcanic eruption, but such deformation, especially in the preliminary phase, can be very subtle. Therefore, surveying techniques, such as DInSAR, that allow for large scale deformation mapping with sub-centimetre accuracy are particularly relevant.

Geodetical monitoring of the Phlegrean Fields, located 25 kilometres west of Vesuvius, has historically been carried out by the Vesuvius Observatory – the world’s oldest volcano observatory – through terrestrial networks. Since 2002, the Observatory has included satellite-derived data in its Surveillance Reports, an innovation following a project with ESA called MINERVA (Monitoring by Interferometric SAR of Environmental Risk in Volcanic Areas).

Geodetic ground networks can provide very high accuracy deformation information, but only within the network layout, so any change in deformation beyond the area covered is lost.

Among the terrestrial methods, levelling, which obtains the vertical component of ground motion, is the oldest. Levelling is based on height measurements carried out on single points called benchmarks, which together constitute the levelling network. The number of benchmarks has been continuously increasing during the last three decades. As a result, the levelling data set of the area is quite large and allows for the retrieval of the geodetic information starting from the end of the 1960s to present.

An extraordinary levelling campaign took place between June and July 2006 in order to verify the uplift trend with about 30 benchmarks being measured for a total path length of some 15 kilometres. The collected data were added to those already available and led to the deformation time series shown in the image to the right that reports the vertical movement in the maximum deformation area from March 1999 to June 2006.

Still, levelling is costly in money and time. Obtaining measurements across a network is a lengthy process - the Phlegrean Fields network has more than 300 benchmarks – as is the consequent data processing. Typically levelling is only carried out once or twice a year.

The poor temporal sampling of terrestrial network data is greatly improved by using DInSAR techniques, considering the revisiting time of satellite sensors with respect to the possible repetition time of field measurements.

The analysis conducted on these satellite observations, together with that obtained by using traditional geodetic measurements, has been transmitted to the Italian Civil Protection as a part of the duty of the Vesuvius Observatory.

To boost the use of Earth Observation data at volcanic observatories ESA has initiated an Invitation to Tender (ITT) to monitor volcanoes worldwide within the framework of the Agency's Data User Element programme. The Globvolcano project will define, implement and validate information services to support volcanological observatories in their daily work by integration of EO data. Services will be related to the different responsibility areas of the users with emphasis on observation and early warning.

Frank Martin Seifert | EurekAlert!
Further information:
http://www.esa.int/esaEO/SEM73AJZBQE_planet_0.html

More articles from Earth Sciences:

nachricht GPM sees deadly tornadic storms moving through US Southeast
01.12.2016 | NASA/Goddard Space Flight Center

nachricht Cyclic change within magma reservoirs significantly affects the explosivity of volcanic eruptions
30.11.2016 | Johannes Gutenberg-Universität Mainz

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>