Source Parameters of the 2016–2017 Central Italy Earthquake Sequence from the Sentinel-1, ALOS-2 and GPS Data

Xu, Guangyu; Xu, Caijun; Wen, Yangmao; Jiang, Gedong

doi:10.3390/rs9111182

Cited by 43 publications

(49 citation statements)

References 31 publications

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“…Among the numerous models for the rupture geometry of the Norcia source on 30 October 2016, proposed in the literature (Cheloni et al, ; Pizzi et al, ; Liu et al, ; Walters et al, ; Xu et al, ), the observed anisotropic results seem to be according to seismogenic source solution proposed by Scognamiglio et al (). In fact, the strike of ϕ axes follows the boundaries of a source modeled on two separated fault planes; δtn peaks are located in correspondence of the south‐western and the northern edges on the second N210° fault (see supporting material for details)…”

Section: Resultsmentioning

confidence: 78%

Shear Wave Splitting Evidence and Relations With Stress Field and Major Faults From the “Amatrice‐Visso‐Norcia Seismic Sequence”

2019

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We present the largest dataset of anisotropic high‐quality parameters (~12,000) for the Amatrice‐Visso‐Norcia seismic sequence and investigate the physical mechanisms causing crustal anisotropy and its relation with crustal deformation, stress field, fluids, and earthquake generation. We performed shear wave splitting analysis on ~40,000 aftershocks recorded at 31 seismic stations during the first six months of the sequence following the 24 August 2016 Mw 6.0, Amatrice mainshock. Automatic and manual‐revised P‐ and S‐picking and high‐precision locations are used to delineate the fracturing pattern and spatio‐temporal variations in the anisotropic parameters: fast direction polarization (φ) and delay time (δt). The mean φ strikes N146°, parallel to the extensional Quaternary fault systems, and to the NW‐SE local active SHmax as proposed by the extensive dilatancy anisotropy model. Locally, φ directions outline the pattern of microscale and mesoscale structures that we relate to structural‐controlled anisotropy. Temporal variations of anisotropic parameters allowed us to deduce stress‐induced and pervasive fluid‐filled stress‐aligned crack systems as the prevalent anisotropic mechanisms in some sectors. Higher δt (>0.072 s) and higher anisotropy percentage (>1.5–2.0%) are found at the boundaries and in the western side of the activated fault systems, where heavily fractured carbonates are present. The fault network along with the lithological heterogeneities present in the area may act as a structural barrier along which fluids are channeled or trapped, thus causing overpressured fluid zones. Observations of shear‐wave splitting parameters during a seismic sequence can monitor the buildup of stress before earthquakes and the stress release as earthquakes occur.

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Section: Resultsmentioning

confidence: 78%

Shear Wave Splitting Evidence and Relations With Stress Field and Major Faults From the “Amatrice‐Visso‐Norcia Seismic Sequence”

2019

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“…An earthquake rupture is a process of releasing and readjusting stress; accordingly, stress readjustment plays an important role in understanding the seismic hazard in a seismogenic region, as has been reported by many studies [12,32,44,45]. Without taking shallow slip into account, the distributed slip model of the 2018 Hokkaido eastern Iburi earthquake evaluated herein was used to calculate the static Coulomb stress change (∆CSC) on the fault plane and in the periphery of the study region using Coulomb 3.3 software [46,47], in order to understand the transfer of stress from deep to shallow depths and assess the regional seismic hazards.…”

Section: Static Coulomb Stress Changes and Seismic Hazardsmentioning

confidence: 94%

“…Nevertheless, robust constraints on the source parameters and slip distribution inversion Remote Sens. 2019, 11,1667 3 of 20 can be supplied with a high accuracy by near-field geodetic measurements, for example, measurements from GNSS stations, which completely record coseismic displacements and interferometric synthetic aperture radar (InSAR) observations with a good spatial coverage [11,12]. Such high-precision coseismic surface observations can provide a valuable opportunity to determine the orientations of seismogenic faults and to develop a deeper understanding of the focal mechanism of this event.…”

Section: Introductionmentioning

confidence: 99%

Fault Slip Model of the 2018 Mw 6.6 Hokkaido Eastern Iburi, Japan, Earthquake Estimated from Satellite Radar and GPS Measurements

Guo

Wen

et al. 2019

Remote Sensing

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In this study, Sentinel-1 and Advanced Land Observation Satellite-2 (ALOS-2) interferometric synthetic aperture radar (InSAR) and global positioning system (GPS) data were used to jointly determine the source parameters and fault slip distribution of the Mw 6.6 Hokkaido eastern Iburi, Japan, earthquake that occurred on 5 September 2018. The coseismic deformation map obtained from the ascending and descending Sentinel-1 and ALOS-2 InSAR data and GPS data is consistent with a thrust faulting event. A comparison between the InSAR-observed and GPS-projected line-of-sight (LOS) deformation suggests that descending Sentinel-1 track T046D, descending ALOS-2 track P018D, and ascending ALOS-2 track P112A and GPS data can be used to invert for the source parameters. The results of a nonlinear inversion show that the seismogenic fault is a blind NNW-trending (strike angle~347.2 • ), east-dipping (dip angle~79.6 • ) thrust fault. On the basis of the optimal fault geometry model, the fault slip distribution jointly inverted from the three datasets reveals that a significant slip area extends 30 km along the strike and 25 km in the downdip direction, and the peak slip magnitude can approach 0.53 m at a depth of 15.5 km. The estimated geodetic moment magnitude released by the distributed slip model is 6.16 × 10 18 N·m, equivalent to an event magnitude of Mw 6.50, which is slightly smaller than the estimates of focal mechanism solutions. According to the Coulomb stress change at the surrounding faults, more attention should be paid to potential earthquake disasters in this region in the near future. In consideration of the possibility of multi-fault rupture and complexity of regional geologic framework, the refined distributed slip and seismogenic mechanism of this deep reverse faulting should be investigated with multi-disciplinary (e.g., geodetic, seismic, and geological) data in further studies.

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“…It ruptured along the northern part of the Mount Vettore fault, the southern portion of which was only partially activated during the 24 August earthquake [8] and was accompanied by numerous aftershocks [13]. Associated slip distribution models all demonstrate a maximum slip exceeding 2.5 m and a concentrated patch of slip located at depths of 0~7 km [8,[12][13][14] corresponding to observed surface fractures [67]. Cheloni et al [8] observed large displacement residuals reaching up to~10 cm within interferograms after jointly inverting the slip along the two segments of the MGVB fault system using GPS and InSAR data.…”

Section: Seismogenic Tectonicsmentioning

confidence: 99%

“…In addition, Chiaraluce et al [13] observed the presence of several shallow antithetic and synthetic faults through the relocation of aftershocks. Xu et al [14] investigated the interactions among the earthquakes through Coulomb failure stress analysis and suggested that the Amatrice earthquake may have triggered the cascading failures of earthquakes along the complex normal fault system.…”

Section: Introductionmentioning

confidence: 99%

Focal Mechanisms of the 2016 Central Italy Earthquake Sequence Inferred from High-Rate GPS and Broadband Seismic Waveforms

Zhong

et al. 2018

Remote Sensing

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Numerous shallow earthquakes, including a multitude of small shocks and three moderate mainshocks, i.e., the Amatrice earthquake on 24 August, the Visso earthquake on 26 October and the Norcia earthquake on 30 October, occurred throughout central Italy in late 2016 and resulted in many casualties and property losses. The three mainshocks were successfully recorded by high-rate Global Positioning System (GPS) receivers located near the epicenters, while the broadband seismograms in this area were mostly clipped due to the strong shaking. We retrieved the dynamic displacements from these high-rate GPS records using kinematic precise point positioning analysis. The focal mechanisms of the three mainshocks were estimated both individually and jointly using high-rate GPS waveforms in a very small epicentral distance range (<100 km) and unclipped regional broadband waveforms (100~600 km). The results show that the moment magnitudes of the Amatrice, Visso, and Norcia events are Mw 6.1, Mw 5.9, and Mw 6.5, respectively. Their focal mechanisms are dominated by normal faulting, which is consistent with the local tectonic environment. The moment tensor solution for the Norcia earthquake demonstrates a significant non-double-couple component, which suggests that the faulting interface is complicated. Sparse network tests were conducted to retrieve stable focal mechanisms using a limited number of GPS records. Our results confirm that high-rate GPS waveforms can act as a complement to clipped near-field long-period seismic waveform signals caused by the strong motion and can effectively constrain the focal mechanisms of moderate-to large-magnitude earthquakes. Thus, high-rate GPS observations extremely close to the epicenter can be utilized to rapidly obtain focal mechanisms, which is critical for earthquake emergency response operations.

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Source Parameters of the 2016–2017 Central Italy Earthquake Sequence from the Sentinel-1, ALOS-2 and GPS Data

Cited by 43 publications

References 31 publications

Shear Wave Splitting Evidence and Relations With Stress Field and Major Faults From the “Amatrice‐Visso‐Norcia Seismic Sequence”

Shear Wave Splitting Evidence and Relations With Stress Field and Major Faults From the “Amatrice‐Visso‐Norcia Seismic Sequence”

Fault Slip Model of the 2018 Mw 6.6 Hokkaido Eastern Iburi, Japan, Earthquake Estimated from Satellite Radar and GPS Measurements

Focal Mechanisms of the 2016 Central Italy Earthquake Sequence Inferred from High-Rate GPS and Broadband Seismic Waveforms

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