Coseismic slip distribution of the 14 January 2021 Mamuju-Majene, Sulawesi, earthquake derived from GPS data

Abstract The 21 May 2021 Maduo earthquake occurred on the Kunlun Mountain Pass–Jiangcuo fault (KMPJF), a seismogenic fault with no documented large earthquakes. To probe its kinematics, we first estimate the slip rates of the KMPJF and Tuosuo Lake segment (TLS, ∼75 km north of the KMPJF) of the East Kunlun fault (EKLF) based on the secular Global Positioning System (GPS) data using the Markov chain Monte Carlo method. Our model reveals that the slip rates of the KMPJF and TLS are 1.7 ± 0.8 and 7.1 ± 0.3 mm/yr, respectively. Then, we invert high-resolution GPS and Interferometric Synthetic Aperture Radar observations to decipher the fault geometry and detailed coseismic slip distribution associated with the Maduo earthquake. The geometry of the KMPFJ significantly varies along strike, composed of five fault subsegments. The most slip is accommodated by two steeply dipping fault segments, with the patch of large sinistral slip concentrated in the shallow depth on a simple straight structure. The released seismic moment is ∼1.5×1020 N·m, equivalent to an Mw 7.39 event, with a peak slip of ∼9.3 m. Combining the average coseismic slip and slip rate of the main fault, an earthquake recurrence period of ∼1250−400+1120 yr is estimated. The Maduo earthquake reminds us to reevaluate the potential of seismic gaps where slip rates are low. Based on our calculated Coulomb failure stress, the Maduo earthquake imposes positive stress on the Maqin–Maqu segment of the EKLF, a long-recognized seismic gap, implying that it may accelerate the occurrence of the next major event in this region.

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Slip Distribution of the 2020 Mw6.9 Samos Earthquake Using a Bayesian Approach

10.5194/egusphere-egu21-14970 ◽

2021 ◽

Author(s):

Figen Eskikoy ◽

Semih Ergintav ◽

Uğur Dogan ◽

Seda Özarpacı ◽

Alpay Özdemir ◽

...

Keyword(s):

Surface Deformation ◽

Fault Plane ◽

Source Parameters ◽

Geodetic Data ◽

Slip Distribution ◽

Double Difference ◽

Gps Data ◽

Analysis Tool ◽

Finite Fault ◽

Continuous Gps

On 2020 October 30, an Mw6.9 earthquake struck offshore&#160;Samos Island. Severe structural damages were observed in Greek Islands and city of Izmir (Turkey). 114 people lost their lives and more than a thousand people were injured in Turkey. The earthquake triggered local tsunami. Significant seismic activity occurred in this region following the earthquake and ~1800 aftershocks (M>1) were recorded by KOERI within the first three days. In this study, we analyze the slip distribution and aftershocks of the 2020 earthquake.For the aftershock relocations, the continuous waveforms were collected from NOA, Disaster and Emergency Management Authority of Turkey (AFAD) and KOERI networks. The database &#160;&#160;was created based on merged catalogs from AFAD and KOERI. For estimating optimized aftershock location distribution, the P and S phases of the aftershocks are picked manually and relocated with double difference algorithm. In addition, source mechanisms of aftershocks M>4 are obtained from regional body and surface waveforms.The surface deformation of the earthquake was obtained from both descending and ascending orbits of the Sentinel-1 A/B and ALOS2 satellites. Since the rupture zone is beneath the Gulf of Kusadas&#305;, earthquake related deformation in the interferograms can only be observed on the northern part of the Samos Island. We processed all possible pairs chose the image pairs with the lowest noise level.In this study, we used 25 continuous GPS stations which are compiled from TUSAGA-Aktif in Turkey and NOANET in Greece. In addition to continuous GPS data, on 2020 November 1, GPS survey was initiated and the earthquake deformation was measured on 10 GNSS campaign sites (TUTGA), along onshore of Turkey.The aim of this study is to estimate the spatial and temporal rupture evolution of the earthquake from geodetic data jointly with near field displacement waveforms. To do so, we use the Bayesian Earthquake Analysis Tool (BEAT).As a first step of the study, rectangular source parameters were estimated by using GPS data. In order to estimate the slip distribution, we used both ascending and descending tracks of Sentinel-1 data, ALOS2 and GPS displacements. In our preliminary geodetic data based finite fault model, we used the results of focal mechanism and GPS data inversion solutions for the initial fault plane parameters. The slip distribution results indicate that earthquake rupture is ~35 km long and the maximum slip is ~2 m normal slip along a north dipping fault plane. This EW trending, ~45&#176; north dipping normal faulting system consistent with this tectonic regime in the region. This seismically active area is part of a N-S extensional regime and controlled primarily by normal fault systems.AcknowledgementsThis work is supported by the Turkish Directorate of Strategy and Budget under the TAM Project number&#160;2007K12-873.

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Coseismic slip and afterslip of the 2015 Mw 8.3 Illapel (Chile) earthquake determined from continuous GPS data

Geophysical Research Letters ◽

10.1002/2016gl070684 ◽

2016 ◽

Vol 43 (20) ◽

pp. 10,710-10,719 ◽

Cited By ~ 20

Author(s):

Mahesh N. Shrivastava ◽

Gabriel González ◽

Marcos Moreno ◽

Mohamed Chlieh ◽

Pablo Salazar ◽

...

Keyword(s):

Gps Data ◽

Coseismic Slip ◽

Chile Earthquake ◽

Continuous Gps

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Insights on fault reactivation during the 2019, Mw4.9 Le Teil earthquake in southeastern France, from a joint 3D geology and InSAR study

10.5194/egusphere-egu21-4388 ◽

2021 ◽

Author(s):

Léo Marconato ◽

Philippe-Hervé Leloup ◽

Cécile Lasserre ◽

Séverine Caritg ◽

Romain Jolivet ◽

...

Keyword(s):

Time Series ◽

Surface Displacement ◽

Fault Reactivation ◽

Least Square ◽

Shallow Depth ◽

Slip Distribution ◽

Fault System ◽

Geological Model ◽

Coseismic Slip ◽

3D Geological Model

<div> <div> <div> The 2019, Mw4.9 Le Teil earthquake occurred in southeastern France, causing important damage in a slow deforming region.&#160;Field based, remote sensing and seismological studies following the event revealed its very shallow depth, a rupture length of ~5 km with surface rupture evidences and a thrusting mechanism. We further investigate this earthquake by combining geological field mapping and 3D geology, InSAR time series analysis and coseismic slip inversion. From structural, stratigraphic and geological data collected around the epicenter, we first produce a 3D geological model over a 70 km2 and 3 km deep zone surrounding the 2019 rupture, using the GeoModeller software. This model includes the geometry of the main faults and geological layers, and especially a geometry for La Rouvi&#232;re Fault, an Oligocene normal fault likely reactivated during the earthquake. We also generate a time series of the surface displacement by InSAR, based on Sentinel-1 data ranging from early January 2019 to late January 2020, using the NSBAS processing chain. The spatio-temporal patterns of the surface displacement for this limited time span show neither clear pre-seismic signal nor significant postseismic slip. We extract from the InSAR time series the coseismic displacement pattern, and in particular the along-strike slip distribution that shows spatial variations. The maximum relative displacement along the Line-Of-Sight is up to ~16 cm and is located in the southwestern part of the rupture. We then invert for the slip distribution on the fault from the InSAR coseismic surface displacement field. We use a non-negative least square approach based on the CSI software and the fault surface trace defined in the 3D geological model, exploring the range of plausible fault dip values. Best-fitting dips range between 55&#176; and 60&#176;. Such values are slightly lower than those measured on La Rouvi&#232;re Fault planes in the field. Our model confirms the reactivation of La Rouvi&#232;re fault, with reverse slip at very shallow depth and two main slip patches reaching 30 cm and 24 cm of slip at 400-500m depth. We finally discuss how the 3D fault geometry and geological configuration could have impacted the slip distribution and propagation during the earthquake. This study is a step to better quantify strain accumulation and assess the seismic hazard associated with other similar faults along the C&#233;vennes fault system, in a densely populated area hosting several nuclear plants. </div> </div> </div>

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Multi-Segment Rupture Model of the 2016 Kumamoto Earthquake Revealed by InSAR and GPS Data

Remote Sensing ◽

10.3390/rs12223721 ◽

2020 ◽

Vol 12 (22) ◽

pp. 3721

Author(s):

Zhongqiu He ◽

Ting Chen ◽

Mingce Wang ◽

Yanchong Li

Keyword(s):

Field Investigation ◽

Slip Distribution ◽

Distribution Model ◽

Coseismic Deformation ◽

Gps Data ◽

Coulomb Stress ◽

2016 Kumamoto Earthquake ◽

Kumamoto Earthquake ◽

The 2016 Kumamoto Earthquake ◽

Stress Changes

The 2016 Kumamoto earthquake, including two large (Mw ≥ 6.0) foreshocks and an Mw 7.0 mainshock, occurred in the Hinagu and Futagawa fault zones in the middle of Kyushu island, Japan. Here, we obtain the complex coseismic deformation field associated with this earthquake from Advanced Land Observation Satellite-2 (ALOS-2) and Sentinel-1A Interferometric Synthetic Aperture Radar (InSAR) data. These InSAR data, in combination with available Global Positioning System (GPS) data, are then used to determine an optimal four-segment fault geometry with the jRi method, which considers both data misfit and the perturbation error from data noise. Our preferred slip distribution model indicates that the rupture is dominated by right-lateral strike-slip, with a significant normal slip component. The largest asperity is located on the northern segment of the Futagawa fault, with a maximum slip of 5.6 m at a 5–6 km depth. The estimated shallow slips along the Futagawa fault and northern Hinagu fault are consistent with the displacements of surface ruptures from the field investigation, suggesting a shallow slip deficit. The total geodetic moment release is estimated to be 4.89 × 1019 Nm (Mw 7.09), which is slightly larger than seismological estimates. The calculated static Coulomb stress changes induced by the preferred slip distribution model cannot completely explain the spatial distribution of aftershocks. Sensitivity analysis of Coulomb stress change implies that aftershocks in the stress shadow area may be driven by aseismic creep or triggered by dynamic stress transfer, requiring further investigation.

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