Ground Displacement Evaluation of the Ischia Island (Phlegraean Volcanic District, Italy) Applying Advanced Satellite SAR Interferometry Techniques

At the very end of the year 2020, on 29 December, a hazardous earthquake of Mw = 6.2 hit the area of Petrinja and its surroundings, in the NW of Croatia. The earthquake was felt across the area of 400 km, leaving an inconceivable damage in the vicinity of the epicenter, devastated towns and ruined lives. In order to map the spreading of earthquake waves and to determine the coseismic ground displacement after the mainshock, we have analyzed open satellite radar images of Sentinel-1 and the GNSS data from the nearest CORS station related to the epicenter, along with the seismic faults. In this paper, we addressed and mapped the displacement linear surface ruptures detected by the SAR interferometry. The results show the vertical ground displacement to the extent of −12 cm in the southern area and up to 22 cm in the north-western part of a wide area struck by the earthquake impact, related to the epicenter. Subsidence and uplift in a range of ±5 cm over a wider affected area indicate a spatial extent and hazardous impact made by the earthquake. The ground displacement of 30 cm to the West and 40 cm to the East has been identified considering the intersection of Pokupsko and Petrinja strike-slip fault system in the seismic zone of Pannonian basin. Accordingly, we obtained matching results of 5 cm south-easting shift and −3 cm subsidence on Sisak GNSS CROPOS station, addressing the tectonic blocks movement along the activated complex fault system. The results compared with the geology data confirm the existence of two main faults; the Pokupsko and the Petrinja strike-slip faults and interpret the occurrence of secondary post-seismic events over the observed area.

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A Preliminary Damage Assessment Using Dual Path Synthetic Aperture Radar Analysis for the M 6.4 Petrinja Earthquake (2020), Croatia

Remote Sensing ◽

10.3390/rs13122267 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2267

Author(s):

Sadra Karimzadeh ◽

Masashi Matsuoka

Keyword(s):

Synthetic Aperture Radar ◽

Sar Interferometry ◽

Synthetic Aperture ◽

Management Service ◽

Ground Displacement ◽

Sar Images ◽

Damage Mapping ◽

Surrounding Areas ◽

The Town ◽

Aperture Radar

On 29 December 2020, an earthquake with a magnitude of M 6.4 hit the central part of Croatia. The earthquake resulted in casualties and damaged buildings in the town of Petrinja (~6 km away from the epicenter) and surrounding areas. This study aims to characterize ground displacement and to estimate the location of damaged areas following the Petrinja earthquake using six synthetic aperture radar (SAR) images (C-band) acquired from both ascending and descending orbits of the Sentinel-1 mission. Phase information from both the ascending (Sentinel-1A) and descending (Sentinel-1B) datasets, acquired from SAR interferometry (InSAR), is used for estimation of ground displacement. For damage mapping, we use histogram information along with the RGB method to visualize the affected areas. In sparsely damaged areas, we also propose a method based on multivariate alteration detection (MAD) and naive Bayes (NB), in which pre-seismic and co-seismic coherence maps and geocoded intensity maps are the main independent variables, together with elevation and displacement maps. For training, approximately 70% of the data are employed and the rest of the data are used for validation. The results show that, despite the limitations of C-band SAR images in densely vegetated areas, the overall accuracy of MAD+NB is ~68% compared with the results from the Copernicus Emergency Management Service (CEMS).

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Drone-borne Differential SAR Interferometry

Remote Sensing ◽

10.3390/rs12050778 ◽

2020 ◽

Vol 12 (5) ◽

pp. 778 ◽

Cited By ~ 5

Author(s):

Dieter Luebeck ◽

Christian Wimmer ◽

Laila F. Moreira ◽

Marlon Alcântara ◽

Gian Oré ◽

...

Keyword(s):

Accuracy Assessment ◽

Sar Interferometry ◽

Atmospheric Effects ◽

Navigation Systems ◽

Ground Displacement ◽

Synthetic Aperture Radar Interferometry ◽

X Band ◽

Aerial Platforms ◽

Differential Sar Interferometry ◽

Better Than

Differential synthetic aperture radar interferometry (DInSAR) has been widely applied since the pioneering space-borne experiment in 1989, and subsequently with the launch of the ERS-1 program in 1992. The DInSAR technique is well assessed in the case of space-borne SAR data, whereas in the case of data acquired from aerial platforms, such as airplanes, helicopters, and drones, the effective application of this technique is still a challenging task, mainly due to the limited accuracy of the information provided by the navigation systems mounted onboard the platforms. The first airborne DInSAR results for measuring ground displacement appeared in 2003 using L- and X-bands. DInSAR displacement results with long correlation time in P-band were published in 2011. This letter presents a SAR system and, to the best of our knowledge, the first accuracy assessment of the DInSAR technique using a drone-borne SAR in L-band. A deformation map is shown, and the accuracy and resolution of the methodology are presented and discussed. In particular, we have obtained an accuracy better than 1 cm for the measurement of the observed ground displacement. It is in the same order as that achieved with space-borne systems in C- and X-bands and the airborne systems in X-band. However, compared to these systems, we use here a much longer wavelength. Moreover, compared to the satellite experiments available in the literature and aimed at assessing the accuracy of the DInSAR technique, we use only two flight tracks with low time decorrelation effects and not a big data stack, which helps in reducing the atmospheric effects.

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Investigation on Volume Scattering for Vegetation Parameter Estimation of Polarimetric SAR Interferometry

PIERS Online ◽

10.2529/piers080907004247 ◽

2009 ◽

Vol 5 (1) ◽

pp. 1-5 ◽

Cited By ~ 2

Author(s):

Yong-sheng Zhou ◽

Wen Hong ◽

Fang Cao

Keyword(s):

Parameter Estimation ◽

Sar Interferometry ◽

Polarimetric Sar ◽

Volume Scattering ◽

Vegetation Parameter ◽

Polarimetric Sar Interferometry

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Combining SAR interferometry and the equation of continuity to estimate the three-dimensional glacier surface-velocity vector

Journal of Glaciology ◽

10.3189/s0022143000001398 ◽

1999 ◽

Vol 45 (151) ◽

pp. 533-538 ◽

Cited By ~ 2

Author(s):

Niels Reeh ◽

Søren Nørvang Madsen ◽

Johan Jakob Mohr

Keyword(s):

Steady State ◽

Mass Balance ◽

Vertical Velocity ◽

Velocity Vector ◽

Thickness Distribution ◽

Vertical Surface ◽

Horizontal Velocity ◽

Sar Interferometry ◽

Surface Velocity ◽

Ice Thickness

AbstractUntil now, an assumption of surface-parallel glacier flow has been used to express the vertical velocity component in terms of the horizontal velocity vector, permitting all three velocity components to be determined from synthetic aperture radar interferometry. We discuss this assumption, which neglects the influence of the local mass balance and a possible contribution to the vertical velocity arising if the glacier is not in steady state. We find that the mass-balance contribution to the vertical surface velocity is not always negligible as compared to the surface-slope contribution. Moreover, the vertical velocity contribution arising if the ice sheet is not in steady state can be significant. We apply the principle of mass conservation to derive an equation relating the vertical surface velocity to the horizontal velocity vector. This equation, valid for both steady-state and non-steady-state conditions, depends on the ice-thickness distribution. Replacing the surface-parallel-flow assumption with a correct relationship between the surface velocity components requires knowledge of additional quantities such as surface mass balance or ice thickness.

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