Long-and Short-Term Deformation Monitoring of Santorini Volcano: Unrest Evidence by DInSAR Analysis

Papageorgiou, Elena; Foumelis, Michael; Parcharidis, Issaak

doi:10.1109/jstars.2012.2198871

Cited by 23 publications

(20 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The H 2 and CO 2 concentrations in the central part of the caldera increased from ~0.01 to ~98.7 mmol/mol and from ~400 to ~500 mmol/mol, respectively; this increase is explained by a convective heat pulse from depth associated with the seismic activation of the NE‐SW oriented Kameni fault, possibly triggered by either injection of new magma or increased permeability of the volcanic plumbing system [ Tassi et al , ]. Joint inversions of SAR and GPS velocities using spherical and spheroidal magmatic source types indicate their location offshore at ~1 km north of Nea Kameni and between 3.5 and 6 km depth [ Papageorgiou et al , ; Newman et al , ; Parks et al , ; Foumelis et al , ; Lagios et al , ]. However, detailed studies on the distribution of the microseismicity during the unrest also might be interpreted as concurrent magma pulses distributed along offset, regional tectonic structures [ Saltogianni et al , ].…”

Section: Types Of Caldera Unrestmentioning

confidence: 99%

An overview of recent (1988 to 2014) caldera unrest: Knowledge and perspectives

Acocella

Lorenzo

Newhall³

et al. 2015

Reviews of Geophysics

155

165

View full text Add to dashboard Cite

Calderas are among the most active and dangerous volcanoes. Caldera unrest is defined by enhanced seismicity, gravity changes, surface deformation, and degassing. Although much caldera unrest does not lead to an eruption, every eruption is preceded by an unrest episode. Therefore, the proper description of unrest and the forecast of its possible outcome is a timely and challenging task. Here we review the best known unrest at calderas from 1988 to 2014, building on previous work and proposing an updated database. Where established, the root cause for unrest is always magmatic; none was purely hydrothermal or tectonic. An interpretive classification of unrest invokes two spectra-compositional (mafic to felsic) and the state of magma conduits feeding from the magma reservoir(s) to the surface (from fully plugged, through semiplugged, to open). Magma and gas in open conduits can rise and erupt freely; magma in semiplugged conduits erupts less frequently yet still allows some gas to escape; plugged conduits allow neither magma nor gas to escape. Unrest in mafic calderas is subtler, less pronounced, and repeated, especially with open systems, ensuring the continuous, aseismic, and moderate release of magma. Plugged felsic calderas erupt infrequently, anticipated by isolated, short and seismically active unrest. Semiplugged felsic calderas also erupt infrequently and are restless over decades or centuries, with uplift, seismicity, and degassing and, on the longer-term, resurgence, suggesting repeated stalled intrusions. Finally, the expected advances in better understanding caldera unrest are discussed.

show abstract

Section: Types Of Caldera Unrestmentioning

confidence: 99%

An overview of recent (1988 to 2014) caldera unrest: Knowledge and perspectives

Acocella

Lorenzo

Newhall³

et al. 2015

Reviews of Geophysics

155

165

View full text Add to dashboard Cite

show abstract

“…For the rest of the volcano, of significant interest is the relatively high westward motion of Cape Skaros, an area that accumulated the highest inflation rates during the 2011-12 unrest [4]. On the basis of the SAR Interferometry results, Nea Kameni remains the area exhibiting the highest ground deformation during the post-unrest period, with higher rates compared to the pre-unrest period (average subsidence rate of −5 ± 0.6 mm/yr for the 1992-2010 period) [3,4,56]. In addition to this, the ongoing deformation at Cape Skaros on the main island indicates that the volcano has not fully recovered yet.…”

Section: Interferometric Resultsmentioning

confidence: 99%

“…The latest volcano's reactivation was followed by the restless period of 2011, which did not culminate in an eruption. Increased microseismic activity [2] and significant ground uplift [3] reaching 14 cm from March 2011 to March 2012 at Cape Skaros (Figure 1), and 9 cm at Nea Kameni islet [4], underlined the seismo-volcanic unrest. Most studies based on geodetic data interpret the episode with a single inflation source due to magma intrusion, at the northern part of the caldera, estimated within 3-4 km depth [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Marine geophysical surveys in the same area provide evidence of shallow intrusions of the post-Minoan activity [27]. The most recent activity of the volcano was recorded at the beginning of 2011 lasting up to the first half of 2012 [3][4][5][6][7][8][9]. This activity was marked by an increase of low magnitude (ML < 3.2) earthquakes, mainly aligned along the Kameni fault [28], deformation and changes in the geochemical parameters of the gas emissions.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multi-Sensor SAR Geodetic Imaging and Modelling of Santorini Volcano Post-Unrest Response

et al. 2019

Self Cite

View full text Add to dashboard Cite

Volcanic history of Santorini over recent years records a seismo-volcanic unrest in 2011-12 with a non-eruptive behavior. The volcano deformation state following the unrest was investigated through multi-sensor Synthetic Aperture Radar Interferometry (InSAR) time series. We focused on the analysis of Copernicus Sentinel-1, Radarsat-2 and TerraSAR-X Multi-temporal SAR Interferometric (MT-InSAR) results, for the post-unrest period 2012-17. Data from multiple Sentinel-1 tracks and acquisition geometries were used to constrain the E-W and vertical components of the deformation field along with their evolution in time. The interpretation of the InSAR observations and modelling provided insights on the post-unrest deformation pattern of the volcano, allowing the further re-evaluation of the unrest event. The increase of subsidence rates on Nea Kameni, in accordance with the observed change of the spatial deformation pattern, compared to the pre-unrest period, suggests the superimposition of various deformation sources. Best-fitting inversion results indicate two deflation sources located at southwestern Nea Kameni at 1 km depth, and in the northern intra-caldera area at 2 km depth. A northern sill-like source interprets the post-unrest deflation attributed to the passive degassing of the magma intruded at 4 km during the unrest, while an isotropic source at Nea Kameni simulates a prevailing subsidence occurring since the pre-unrest period (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010).

show abstract

“…Processing of SAR data was performed using the GAMMA software packages [22], following commonly applied chains in deformation related studies [23,24]. An important aspect of the processing was the estimation of the coherence using an adaptive procedure as described in [25].…”

Section: Processing On Esa's G-podmentioning

confidence: 99%

Moving from Temporal Coherence to Decorrelation Time of Interferometric Measurements Exploiting ESA?s SAR Archive

Foumelis

Mitraka

Cuccu

et al. 2015

Proceedings of Fringe 2015: Advances in the Science and Applications of SAR Interferometry and Sentinel-1 InSAR Workshop

Self Cite

View full text Add to dashboard Cite

Interferometric coherence can be considered as an expression of temporal decorrelation. It is understood that interferometric coherence decreases with time between SAR acquisitions because of changes in surface reflectivity, reducing the quality of SAR phase measurements. This is an intrinsic characteristic of the design of SAR systems that has a significant contribution at longer time scales. Although in the past there was not sufficient amount of SAR data to extract robust statistical metrics for decorrelation, in the present study it is demonstrated that tailored analysis of interferometric coherence exploiting the large SAR archive available by the European Space Agency (ESA), enables the accurate quantification of temporal decorrelation. A methodology to translate the observed rate of coherence loss into decorrelation times over a volcanic landscape, namely the Santorini volcanic complex is the subject treated in this study. Specifically, a sensitivity analysis was performed on a large data stack of interferometric pairs to quantify at a pixel level the time beyond which the interferometric phase becomes practically unusable due to the effect of decorrelation. Though the dependence of decorrelation on various land cover/use types is already documented the provision of additional information regarding the expected time of decorrelation is of practical use especially when EO data are utilized in operational activities. The performed analysis is viewed within the improved capacity of current and future SAR systems, while underlining the necessity for exploitation of archive data.

show abstract

Long-and Short-Term Deformation Monitoring of Santorini Volcano: Unrest Evidence by DInSAR Analysis

Cited by 23 publications

References 11 publications

An overview of recent (1988 to 2014) caldera unrest: Knowledge and perspectives

An overview of recent (1988 to 2014) caldera unrest: Knowledge and perspectives

Multi-Sensor SAR Geodetic Imaging and Modelling of Santorini Volcano Post-Unrest Response

Moving from Temporal Coherence to Decorrelation Time of Interferometric Measurements Exploiting ESA?s SAR Archive

Contact Info

Product

Resources

About