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We investigate a large geodetic data set of interferometric synthetic aperture radar (InSAR) and GPS measurements to determine the source parameters for the three main shocks of the 2016 Central Italy earthquake sequence on 24 August and 26 and 30 October (Mw 6.1, 5.9, and 6.5, respectively). Our preferred model is consistent with the activation of four main coseismic asperities belonging to the SW dipping normal fault system associated with the Mount Gorzano-Mount Vettore-Mount Bove alignment. Additional slip, equivalent to a Mw ~ 6.1–6.2 earthquake, on a secondary (1) NE dipping antithetic fault and/or (2) on a WNW dipping low-angle fault in the hanging wall of the main system is required to better reproduce the complex deformation pattern associated with the greatest seismic event (the Mw 6.5 earthquake). The recognition of ancillary faults involved in the sequence suggests a complex interaction in the activated crustal volume between the main normal faults and the secondary structures and a partitioning of strain release.

[1] We provide new insights into the two main seismic events that occurred in 2012 in the Emilia region, Italy. We extend the results from previous studies based on analytical inversion modeling of GPS and RADARSAT-1 InSAR measurements by exploiting RADARSAT-2 data. Moreover, we benefit from the available large amount of geological and geophysical information through finite element method (FEM) modeling implemented in a structural-mechanical context to investigate the impact of known buried structures on the modulation of the ground deformation field. We find that the displacement pattern associated with the 20 May event is consistent with the activation of a single fault segment of the inner Ferrara thrust, in good agreement with the analytical solution. In contrast, the interpretation of the 29 May episode requires the activation of three different fault segments and a block roto-translation of the Mirandola anticline. The proposed FEM-based methodology is applicable to other seismic areas where the complexity of buried structures is known and plays a fundamental role in the modulation of the associated surface deformation pattern.

[1] We investigate the surface displacements in the area affected by the April 2009 L'Aquila earthquake (Central Italy) through an advanced DInSAR analysis. In particular, we apply the SBAS approach to retrieve deformation maps and displacement time series from ENVISAT data acquired between February 2003 and October 2009 and from COSMO-SkyMed data relevant to the six-month interval following the earthquake. Our analysis shows no evidence of pre-seismic surface deformation at the 35-day temporal sampling of the ENVISAT sensor. On the other hand, by benefiting of the high spatial resolution and temporal sampling of the COSMO-SkyMed satellites, we measure post-seismic displacements at an unprecedented level of detail for a DInSAR analysis. This allows us to identify three main areas continuing to deform after the earthquake. In addition, our modeling shows that post-seismic displacements are very likely related to the fault afterslip, since their decay times are on the order of 101–102 days.

We study the state of deformation of Tenerife (Canary Islands) using Differential Synthetic Aperture Radar Interferometry (DInSAR). We apply the Small BAseline Subset (SBAS) DInSAR algorithm to radar images acquired from 1992 to 2005 by the ERS sensors to determine the deformation rate distribution and the time series for the coherent pixels identified in the island. Our analysis reveals that the summit area of the volcanic edifice is characterized by a rather continuous subsidence extending well beyond Las Cañadas caldera rim and corresponding to the dense core of the island. These results, coupled with GPS ones, structural and geological information and deformation modeling, suggest an interpretation based on the gravitational sinking of the dense core of the island into a weak lithosphere and that the volcanic edifice is in a state of compression. We also detect more localized deformation patterns correlated with water table changes and variations in the deformation time series associated with the seismic crisis in 2004.

[1] We investigate the 2004–2006 uplift phase of Campi Flegrei caldera (Italy) by exploiting the archive of ascending and descending ENVISAT SAR data acquired from November 2002 to November 2006. The SBAS-DInSAR technique is applied to generate displacement mean velocity maps and time series. An appropriate post-processing step is subsequently applied to map the areas whose temporal deformation behavior is correlated with that of the maximum uplift zone. Our results show that the deformation also extends outside the volcanological limits of the Neapolitan Yellow Tuff caldera, without significant discontinuities. The DInSAR data are inverted by considering a finite spheroid and an isotropic point-source. The inversion results suggest that the new uplift is characterized by a source location similar to the previous small uplift event of 2000 and to the long term subsidence of the 1990's. In particular, the source is located at a depth of about 3.2 km and very close to the city of Pozzuoli (about 800 m offshore, to the SW); the associated volume variation is about 1.1 106 m3/year.

[1] We use the Small BAseline Subset (SBAS) InSAR algorithm to obtain radar line-of-sight deformation velocities for two adjacent SAR swaths and invert the data for the 2-D velocity field in vertical and ground range direction. The analysis reveals areas of rapid deformation caused by mining and agricultural activities in the Crescent Valley, Nevada, USA. The LOS displacements of up to 25 centimeters during the 1992–2002 period are caused by vertical and horizontal deformation. About 8 mm/yr horizontal velocity is detected 10 km from the BARGEN GPS site LEWI suggesting that the GPS station may be moving in response to the water pumping. In the Basin and Range anthropogenic ground deformation can extend several tens of kilometers from the basins into the bedrock of the Ranges.

[1] We integrate geologic, structural, leveling and Differential SAR Interferometry data to show that Vesuvius began to spread onto its sedimentary substratum about 3,600 years ago. Moreover, we model the detected deformation with a solution of the lubrication approximation of the Navier-Stokes equations to show that spreading may continue for about 7,200 years more. Correlation of volcanic spreading with phases of the eruptive activity suggests that Plinian eruptions, which are thought to pose the major hazard, are less likely to occur in the near future.

[1] The Los Angeles, California, metropolitan area is a tectonically active region with surface deformation that is a combination of fault related tectonics plus a variety of natural and anthropogenic signals. We apply the small baseline subset (SBAS) algorithm to produce an interferometric synthetic aperture radar (InSAR) time series analysis for the Los Angeles area using data acquired by the ERS satellites from late 1995 into 2002. The result is a space-time deformation product that can be exploited to view not only the smoothly varying long-term surface motion, but also its time varying patterns. Large seasonal oscillations of the Santa Ana aquifer observed in Southern California Integrated GPS Network (SCIGN) data are accurately matched in the InSAR time series, moreover, correlations of the InSAR time series with an annual sinusoid allows us to investigate the dynamics of the hydrologic system. INDEX TERMS: 1243 Geodesy and Gravity: Space geodetic surveys; 1294 Geodesy and Gravity: Instruments and techniques; 1803 Hydrology: Anthropogenic effects. Citation: Lanari, R., P. Lundgren, M. Manzo, and F. Casu (2004), Satellite radar interferometry time series analysis of surface deformation for Los Angeles, California, Geophys. Res. Lett., 31, L23613, doi:10.1029/2004GL021294.