Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Renewed volcanic activity at the Phlegrean Fields tracked by Envisat

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:

More articles from Earth Sciences:

nachricht UCI and NASA document accelerated glacier melting in West Antarctica
26.10.2016 | University of California - Irvine

nachricht Ice shelf vibrations cause unusual waves in Antarctic atmosphere
25.10.2016 | American Geophysical Union

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

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

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

How nanoscience will improve our health and lives in the coming years

27.10.2016 | Materials Sciences

OU-led team discovers rare, newborn tri-star system using ALMA

27.10.2016 | Physics and Astronomy

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

More VideoLinks >>>