Calcareous inclusions in lavas and agglomerates of Santorini volcano

1971 ◽  
Vol 30 (4) ◽  
pp. 261-276 ◽  
Author(s):  
I. A. Nicholls
Keyword(s):  
Santorini Volcano

Modelling of interactions between dykes, inclined sheets and faults at Santorini volcano

2021 ◽  
Author(s):  
Kyriaki Drymoni ◽  
John Browning ◽  
Agust Gudmundsson
Keyword(s):  
Tensile Strength ◽  
Fault Zone ◽  
Numerical Models ◽  
Damage Zone ◽  
Sheet Thickness ◽  
Analytical Models ◽  
Energy Conditions ◽  
Dyke Swarm ◽  
Normal Faults ◽  
Santorini Volcano

<p>Dykes and inclined sheets are known occasionally to exploit faults as parts of their paths, but the conditions that allow this to happen are still not fully understood. Here we report field observations from a well-exposed dyke swarm of the Santorini volcano, Greece, that show dykes and inclined sheets deflected into faults and the results of analytical and numerical models to explain the conditions for deflection. The deflected dykes and sheets belong to a local swarm of 91 dyke/sheet segments that was emplaced in a highly heterogeneous and anisotropic host rock and partially cut by some regional faults and a series of historic caldera collapses, the caldera walls providing, excellent exposures of the structures. The numerical models focus on a normal-fault dipping 65° with a damage zone composed of parallel layers or zones of progressively more compliant rocks with increasing distance from the fault rupture plane. We model sheet-intrusions dipping from 0˚ to 90˚ and with overpressures of alternatively 1 MPa and 5 MPa, approaching the fault. We further tested the effects of changing (1) the sheet thickness, (2) the fault-zone thickness, (3) the fault-zone dip-dimension (height), and (4) the loading by, alternatively, regional extension and compression. We find that the stiffness of the fault core, where a compliant core characterises recently active fault zones, has pronounced effects on the orientation and magnitudes of the local stresses and, thereby, on the likelihood of dyke/sheet deflection into the fault zone. Similarly, the analytical models, focusing on the fault-zone tensile strength and energy conditions for dyke/sheet deflection, indicate that dykes/sheets are most likely to be deflected into and use steeply dipping recently active (zero tensile-strength) normal faults as parts of their paths.</p>

scholarly journals Sentinel-1 Monitoring of Santorini Volcano Post-Unrest State

2018 ◽  
Author(s):  
Elena Papageorgiou ◽  
Michael Foumelis ◽  
Antonios Mouratidis ◽  
Costas Papazachos
Keyword(s):  
Santorini Volcano

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

2019 ◽  
Vol 11 (3) ◽  
pp. 259 ◽  
Author(s):  
Elena Papageorgiou ◽  
Michael Foumelis ◽  
Elisa Trasatti ◽  
Guido Ventura ◽  
Daniel Raucoules ◽  
...  
Keyword(s):  
Deformation Pattern ◽  
Volcano Deformation ◽  
Isotropic Source ◽  
Synthetic Aperture Radar Interferometry ◽  
Spatial Deformation ◽  
Deformation State ◽  
Multi Temporal ◽  
History Of ◽  
Best Fitting ◽  
Santorini Volcano

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 (1992–2010).

scholarly journals Rapid emergency assessment of ash and gas hazard for future eruptions at Santorini Volcano, Greece

2015 ◽  
Vol 4 (1) ◽  
Author(s):  
S F Jenkins ◽  
S Barsotti ◽  
T K Hincks ◽  
A Neri ◽  
J C Phillips ◽  
...  
Keyword(s):  
Gas Hazard ◽  
Santorini Volcano

SqueeSAR™ and GPS ground deformation monitoring of Santorini Volcano (1992–2012): Tectonic implications

2013 ◽  
Vol 594 ◽  
pp. 38-59 ◽  
Author(s):  
E. Lagios ◽  
V. Sakkas ◽  
F. Novali ◽  
F. Bellotti ◽  
A. Ferretti ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Deformation Monitoring ◽  
Tectonic Implications ◽  
Ground Deformation Monitoring ◽  
Santorini Volcano

scholarly journals Seismic observations with broadband instruments at Santorini volcano

2018 ◽  
Vol 40 (3) ◽  
pp. 1150 ◽  
Author(s):  
A. Kolaitis ◽  
P. Papadimiriou ◽  
I. Kassaras ◽  
K. Makropoulos
Keyword(s):  
Low Frequency ◽  
Volcanic Tremor ◽  
Velocity Model ◽  
Dominant Frequency ◽  
Depth Range ◽  
Traveltime Inversion ◽  
Time Frequency ◽  
Inversion Procedure ◽  
Santorini Volcano ◽  
Better Than

Two arrays equipped with broadband sensors were installed for a period of 10 months, in order to study the seismic activity in the area of Santorini (Thira) volcano. During these periods, about 330 earthquakes were recorded and located within a radius of 50 km from the center of the caldera. An iterative damped traveltime inversion procedure yielded a local 1-D Ρ-wave velocity model and improved locations with an accuracy better than 5 Km in both horizontal and vertical components for 135 earthquakes. Those are mainly distributed within a depth range 5-18 Km, in the vicinity of the submarine Kolumbo Reef (NE of Santorini Island). Signal analysis of the recorded volcanic earthquakes including typical Fourier transformations and several operations in the time-frequency domain, allowed their dominant frequency determination and their classification into three groups based on waveform appearance and frequency content: (1) highfrequency events; (2) low-frequency events; and (3) volcanic tremor. Frequencytime analysis of tremor, detected at three stations, revealed two kinds of harmonic tremor with one sharp peak, at 3-5 Hz and 8.5-10 Hz.

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