scholarly journals Fault Pattern and Seismotectonic Style of the Campania – Lucania 1980 Earthquake (Mw 6.9, Southern Italy): New Multidisciplinary Constraints

2021 ◽  
Vol 8 ◽  
Author(s):  
S. Bello ◽  
R. de Nardis ◽  
R. Scarpa ◽  
F. Brozzetti ◽  
D. Cirillo ◽  
...  
Keyword(s):  
Hanging Wall ◽  
Active Faults ◽  
Stress Transfer ◽  
Normal Fault ◽  
Vertical Displacement ◽  
Seismic Profile ◽  
Seismogenic Fault ◽  
Epicentral Area ◽  
Fault Pattern ◽  
Main Fault

New fault trace mapping and structural survey of the active faults outcropping within the epicentral area of the Campania-Lucania 1980 normal fault earthquake (Mw 6.9) are integrated with a revision of pre-existing earthquake data and with an updated interpretation of the CROP-04 near-vertical seismic profile to reconstruct the surface and depth geometry, the kinematics and stress tensor of the seismogenic fault pattern. Three main fault alignments, organized in high-angle en-echelon segments of several kilometers in length, are identified and characterized. The inner and intermediate ones, i.e. Inner Irpinia (InIF) and Irpinia Faults (IF), dip eastward; the outer Antithetic Fault (AFA) dips westward. Both the InIF and the IF strike NW-SE along the northern and central segments and rotate to W-E along the southern segments for at least 16 km. We provide evidence of surface coseismic faulting (up to 1 m) not recognized before along the E-W segments and document coseismic ruptures with maximum vertical displacement up to ∼1 m where already surveyed from other investigators 40 years ago. Fault/slip data from surface data and a new compilation of focal mechanisms (1980 – 2018) were used for strain and stress analyses to show a coherent NNE-directed least principal stress over time and at different crustal depths, with a crustal-scale deviation from the classic SW-NE tensional direction across the Apennines of Italy. The continuation at depth of the outcropping faults is analyzed along the trace of the CROP-04 profile and with available hypocentral distributions. Integrating all information, a 3D seismotectonic model, extrapolated to the base of the seismogenic layer, is built. It outlines a graben-like structure with a southern E-W bend developed at depth shallower than 10–12 km, at the hanging wall of an extensional NE- to E-dipping extensional basal detachment. In our interpretation, such a configuration implies a control in the stress transfer during the 1980 earthquake ruptures and provides a new interpretation of the second sub-event, occurred at 20 s. Our reconstruction suggests that the latter ruptured a hanging wall NNE-dipping splay of the E-W striking main fault segment and possibly also an antithetic SSW-dipping splay, in two in-sequence episodes.

scholarly journals Multiple Lines of Evidence for a Potentially Seismogenic Fault Along the Central-Apennine (Italy) Active Extensional Belt–An Unexpected Outcome of the MW6.5 Norcia 2016 Earthquake

2021 ◽  
Vol 9 ◽  
Author(s):  
Federica Ferrarini ◽  
Rita de Nardis ◽  
Francesco Brozzetti ◽  
Daniele Cirillo ◽  
J Ramón Arrowsmith ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Tectonic Setting ◽  
Central Italy ◽  
Stress Transfer ◽  
Normal Fault ◽  
Normal Faults ◽  
Coulomb Stress ◽  
Seismic Sequence ◽  
Seismogenic Fault ◽  
Seismogenic Source

The Apenninic chain, in central Italy, has been recently struck by the Norcia 2016 seismic sequence. Three mainshocks, in 2016, occurred on August 24 (MW6.0), October 26 (MW 5.9) and October 30 (MW6.5) along well-known late Quaternary active WSW-dipping normal faults. Coseismic fractures and hypocentral seismicity distribution are mostly associated with failure along the Mt Vettore-Mt Bove (VBF) fault. Nevertheless, following the October 26 shock, the aftershock spatial distribution suggests the activation of a source not previously mapped beyond the northern tip of the VBF system. In this area, a remarkable seismicity rate was observed also during 2017 and 2018, the most energetic event being the April 10, 2018 (MW4.6) normal fault earthquake. In this paper, we advance the hypothesis that the Norcia seismic sequence activated a previously unknown seismogenic source. We constrain its geometry and seismogenic behavior by exploiting: 1) morphometric analysis of high-resolution topographic data; 2) field geologic- and morphotectonic evidence within the context of long-term deformation constraints; 3) 3D seismological validation of fault activity, and 4) Coulomb stress transfer modeling. Our results support the existence of distributed and subtle deformation along normal fault segments related to an immature structure, the Pievebovigliana fault (PBF). The fault strikes in NNW-SSE direction, dips to SW and is in right-lateral en echelon setting with the VBF system. Its activation has been highlighted by most of the seismicity observed in the sector. The geometry and location are compatible with volumes of enhanced stress identified by Coulomb stress-transfer computations. Its reconstructed length (at least 13 km) is compatible with the occurrence of MW≥6.0 earthquakes in a sector heretofore characterized by low seismic activity. The evidence for PBF is a new observation associated with the Norcia 2016 seismic sequence and is consistent with the overall tectonic setting of the area. Its existence implies a northward extent of the intra-Apennine extensional domain and should be considered to address seismic hazard assessments in central Italy.

scholarly journals Structural characterization of fault damage zones in carbonates (Central Apennines, Italy)

2021 ◽  
Author(s):  
Miriana Chinello ◽  
Michele Fondriest ◽  
Giulio Di Toro
Keyword(s):  
Fault Zone ◽  
Hanging Wall ◽  
Damage Zone ◽  
Normal Fault ◽  
Vertical Displacement ◽  
Fault System ◽  
Normal Faults ◽  
Central Apennines ◽  
Fault Surface ◽  
Fracture Intensity

<p>The Italian Central Apennines are one of the most seismically active areas in the Mediterranean (e.g., L’Aquila 2009, Mw 6.3 earthquake). The mainshocks and the aftershocks of these earthquake sequences propagate and often nucleate in fault zones cutting km-thick limestones and dolostones formations. An impressive feature of these faults is the presence, at their footwall, of few meters to hundreds of meters thick damage zones. However, the mechanism of formation of these damage zones and their role during (1) individual seismic ruptures (e.g., rupture arrest), (2) seismic sequences (e.g., aftershock evolution) and (3) seismic cycle (e.g., long term fault zone healing) are unknown. This limitation is also due to the lack of knowledge regarding the distribution, along strike and with depth, of damage with wall rock lithology, geometrical characteristics (fault length, inherited structures, etc.) and kinematic properties (cumulative displacement, strain rate, etc.) of the associated main faults.</p><p>Previous high-resolution field structural surveys were performed on the Vado di Corno Fault Zone, a segment of the ca. 20 km long Campo Imperatore normal fault system, which accommodated ~ 1500 m of vertical displacement (Fondriest et al., 2020). The damage zone was up to 400 m thick and dominated by intensely fractured (1-2 cm spaced joints) dolomitized limestones with the thickest volumes at fault oversteps and where the fault cuts through an older thrust zone. Here we describe two minor faults located in the same area (Central Apennines), but with shorter length along strike. They both strike NNW-SSE and accommodated a vertical displacement of ~300 m.</p><p>The Subequana Valley Fault is about 9 km long and consists of multiple segments disposed in an en-echelon array. The fault juxtaposes pelagic limestones at the footwall and quaternary deposits at the hanging wall. The damage zone is < 25 m  thick  and comprises fractured (1-2 cm spaced joints) limestones beds with decreasing fracture intensity moving away from the master fault. However, the damage zone thickness increases up to ∼100 m in proximity of subsidiary faults striking NNE-SSW. The latter could be reactivated inherited structures.</p><p>The Monte Capo di Serre Fault is about 8 km long and characterized by a sharp ultra-polished master fault surface which cuts locally dolomitized Jurassic platform limestones. The damage zone is up to 120 m thick and cut by 10-20 cm spaced joints, but it reaches an higher fracture intensity where is cut by subsidiary, possibly inherited, faults striking NNE-SSW.</p><p>Based on these preliminary observations, faults with similar displacement show comparable damage zone thicknesses. The most relevant damage zone thickness variations are related to geometrical complexities rather than changes in lithology (platform vs pelagic carbonates).  In particular, the largest values of damage zone thickness and fracture intensity occur at fault overstep or are associated to inherited structures. The latter, by acting as strong or weak barriers (sensu Das and Aki, 1977) during the propagation of seismic ruptures, have a key role in the formation of damage zones and the growth of normal faults.</p>

The epicentral fingerprint of earthquakes

2021 ◽  
Author(s):  
Patrizio Petricca ◽  
Christian Bignami ◽  
Carlo Doglioni
Keyword(s):  
Seismic Waves ◽  
Hanging Wall ◽  
Vertical Displacement ◽  
Strike Slip ◽  
Coseismic Deformation ◽  
Far Field ◽  
Ground Acceleration ◽  
Epicentral Area ◽  
Local Site ◽  
Field Area

<p>InSAR images allow to detect the coseismic deformation, delimiting the epicentral area where the larger displacement has been concentrated. The main observations are: 1) the most deformed area in the ideal case is elliptical (for dip-slip faults) or quadrilobated (for strike-slip faults) and coincides with the surface projection of the volume coseismically mobilized in the hanging wall of thrusts and normal faults, or the crustal walls adjacent to strike-slip faults; 2) the dimension of the deformed area detected by InSAR scales with magnitude of earthquake and for M≥6 is always larger than 100 km, increasing to more than 550 km<sup>2</sup> for M≈6.5; 3) the seismic epicenter rarely coincide with the area of larger vertical shaking (either downward or upward); 4) the higher macroseismic intensity corresponds to the area of larger vertical displacement, apart from local site amplification effects; 5) outside this area, the vertical displacement is drastically lower, determining the strong attenuation of seismic waves and the decrease of the peak ground acceleration in the surrounding far field area, apart from local site amplifications; 6) the segment of the activated fault constrains the area where the vertical oscillations have been larger, allowing the contemporaneous maximum freedom degree of the crustal volume affected by horizontal maximum shaking, i.e., the near field or epicentral area; 7) therefore, the epicentral area and volume are active, i.e., they coseismically move and are contemporaneously crossed by seismic waves (active volume), whereas the surrounding far field area is mainly fixed and passively crossed by seismic waves (passive volume). Therefore, here we show how the InSAR images of areas affected by earthquakes represent the fingerprint of the epicentral area where the largest shaking has taken place during an earthquake. Seismic hazard assessments should rely on those data.</p>

scholarly journals On the mechanical behaviour of a low-angle normal fault: the Alto Tiberina fault (Northern Apennines, Italy) system case study

Solid Earth ◽  
2016 ◽  
Vol 7 (6) ◽  
pp. 1537-1549 ◽  
Author(s):  
Luigi Vadacca ◽  
Emanuele Casarotti ◽  
Lauro Chiaraluce ◽  
Massimo Cocco
Keyword(s):  
Mechanical Behaviour ◽  
Hanging Wall ◽  
Normal Fault ◽  
Active Role ◽  
Northern Apennines ◽  
Fault System ◽  
Tectonically Active ◽  
Main Fault ◽  
Microseismic Activity ◽  
High Degree

Abstract. Geological and seismological observations have been used to parameterize 2-D numerical elastic models to simulate the interseismic deformation of a complex extensional fault system located in the Northern Apennines (Italy). The geological system is dominated by the presence of the Alto Tiberina fault (ATF), a large (60 km along strike) low-angle normal fault dipping 20° in the brittle crust (0–15 km).  The ATF is currently characterized by a high and constant rate of microseismic activity, and no moderate-to-large magnitude earthquakes have been associated with this fault in the past 1000 years. Modelling results have been compared with GPS data in order to understand the mechanical behaviour of this fault and a suite of minor syn- and antithetic normal fault segments located in the main fault hanging wall. The results of the simulations demonstrate the active role played by the Alto Tiberina fault in accommodating the ongoing tectonic extension in this sector of the chain. The GPS velocity profile constructed through the fault system cannot be explained without including the ATF's contribution to deformation, indicating that this fault, although misoriented, has to be considered tectonically active and with a creeping behaviour below 5 km depth. The low-angle normal fault also shows a high degree of tectonic coupling with its main antithetic fault (the Gubbio fault), suggesting that creeping along the ATF may control the observed strain localization and the pattern of microseismic activity.

scholarly journals Joint Interpretation of Geophysical Results and Geological Observations for Detecting Buried Active Faults: The Case of the “Il Lago” Plain (Pettoranello del Molise, Italy)

2021 ◽  
Vol 13 (8) ◽  
pp. 1555
Author(s):  
Rosa Nappi ◽  
Valeria Paoletti ◽  
Donato D’Antonio ◽  
Francesco Soldovieri ◽  
Luigi Capozzoli ◽  
...  
Keyword(s):  
Seismic Tomography ◽  
Active Faults ◽  
Low Frequency ◽  
Normal Fault ◽  
Seismic Source ◽  
Fault System ◽  
Normal Faults ◽  
Macroseismic Data ◽  
Epicentral Area ◽  
Seismogenic Source

We report a geophysical study across an active normal fault in the Southern Apennines. The surveyed area is the “Il Lago” Plain (Pettoranello del Molise), at the foot of Mt. Patalecchia (Molise Apennines, Southern Italy), a small tectonic basin filled by Holocene deposits located at the NW termination of the major Quaternary Bojano basin structure. This basin, on the NE flank of the Matese Massif, was the epicentral area of the very strong 26 July, 1805, Sant’Anna earthquake (I0 = X MCS, Mw = 6.7). The “Il Lago” Plain is bordered by a portion of the right-stepping normal fault system bounding the whole Bojano Quaternary basin (28 km long). The seismic source responsible for the 1805 earthquake is regarded as one of the most hazardous structures of the Apennines; however, the position of its NW boundary of this seismic source is debated. Geological, geomorphological and macroseismic data show that some coseismic surface faulting also occurred in correspondence with the border fault of the “Il Lago” Plain. The study of the “Il Lago” Plain subsurface might help to constrain the NW segment boundary of the 1805 seismogenic source, suggesting that it is possibly a capable fault, source for moderate (Mw < 5.5) to strong earthquakes (Mw ≥ 5.5). Therefore, we constrained the geometry of the fault beneath the plain using low-frequency Ground Penetrating Radar (GPR) data supported by seismic tomography. Seismic tomography yielded preliminary information on the subsurface structures and the dielectric permittivity of the subsoil. A set of GPR parallel profiles allowed a quick and high-resolution characterization of the lateral extension of the fault, and of its geometry at depth. The result of our study demonstrates the optimal potential of combined seismic and deep GPR surveys for investigating the geometry of buried active normal faults. Moreover, our study could be used for identifying suitable sites for paleoseismic analyses, where record of earthquake surface faulting might be preserved in Holocene lacustrine sedimentary deposits. The present case demonstrates the possibility to detect with high accuracy the complexity of a fault-zone within a basin, inferred by GPR data, not only in its shallower part, but also down to about 100 m depth.

Faulting, doming and basin formation during orogenic arcuation – the case of the Shkoder-Peja Normal Fault System (northern Albania and Kosovo)

2021 ◽  
Author(s):  
Marc U. Grund ◽  
Mark R. Handy ◽  
Jörg Giese ◽  
Jan Pleuger ◽  
Lorenzo Gemignani ◽  
...  
Keyword(s):  
Hanging Wall ◽  
Normal Fault ◽  
Sedimentary Basins ◽  
Vertical Displacement ◽  
Ductile Deformation ◽  
Fault System ◽  
Normal Faulting ◽  
Two Phase ◽  
Brittle Faulting ◽  
Topographic Constraints

&lt;p&gt;The junction between the Dinarides and the Hellenides coincides with an orogenic bend characterized by a complex system of faults, domes and sedimentary basins. The major structure at this junction is the Shkoder-Peja Normal Fault (SPNF) system, which trends oblique to the orogen and is segmented along strike, with ductile-to-brittle branches in its southwestern and central parts that border two domes in its footwall: (1) the Cukali Dome (RSCM peak-T 190-280&amp;#176;C), a doubly-plunging upright antiform deforming Dinaric nappes, including the Krasta-Cukali nappe with its Middle Triassic to Early Eocene sediments; (2) the newly discovered Decani Dome (RSCM peak-T 320-460&amp;#176;C) delimited to the E by the ~1500 m wide Decani Shear Zone (DSZ) that exposes Paleozoic to Mesozoic strata of the East Bosnian Durmitor nappe (EBD). In the northeasternmost segment, the strike of the SPNF system changes from roughly orogen-perpendicular to orogen-parallel. There, the SPNF system has brittle branches- most notably the Dukagjini Fault (DF) that forms the northwestern limit of the Western Kosovo Basin (WKB).&lt;/p&gt;&lt;p&gt;The westernmost ductile-brittle SPNF segment strikes along the southern limb of the Cukali Dome with an increasing vertical offset from 0 m near Shkoder eastwards to &gt;1000 m at the eastern extent of the dome (near Fierza) where normal faulting cuts the nappe contact between the High Karst and Krasta-Cukali unit. The central segment north of the Tropoja Basin, with several smaller branches changing in strike, has a vertical throw of at least 1500 meters based on topographic constraints. Even further to the northeast, the SPNF system includes the moderately E-dipping DSZ juxtaposing the EBD in its footwall against m&amp;#232;lange of the West Vardar unit in its hanging wall, where offset is difficult to determine. 3 km eastwards, in the hanging wall to the DSZ, the brittle DF accommodates another 1000 m of vertical displacement as constrained by maximum depth of sediments of the WKB.&lt;/p&gt;&lt;p&gt;Ductile deformation along the Cukali and Decani Domes occurred sometime between the end of Dinaric thrusting and the formation of the WKB. Brittle faulting partly reactivates ductile segments, but also creates new branches (DF) within the hanging wall of the ductile DSZ. These were active during mid-Miocene to Pliocene times as constrained by syn-tectonic sediments in the WKB. We interpret the SPNF system as a two-phase composite extensional structure with normal faulting that migrated from its older trace along the ductile DSZ to the brittle DF as indicated by cross-cutting relations. The Decani Dome, with higher metamorphic temperature conditions than the Cukali Dome, may reflect the south-westernmost extent of late Paleogene extension in the Dinarides. It may be related to other core complexes and possibly to limited subduction rollback beneath the Dinarides (Matenco and Radivojevi, 2012). Extension from mid-Miocene time onwards was probably related to Hellenic CW rotation during Neogene orogenic arcuation, possibly triggered by enhanced rollback beneath the Hellenides (Handy et al., 2019).&lt;/p&gt;&lt;p&gt;Handy, M.R.,et al. 2019: Tectonics, v. 38, p. 2803&amp;#8211;2828, doi:10.1029/2019TC005524.&lt;/p&gt;&lt;p&gt;Matenco, L.,&amp; Radivojevi, D. 2012: Tectonics, v. 31, p. 1&amp;#8211;31, doi:10.1029/2012TC003206.&lt;/p&gt;

scholarly journals On the mechanical behaviour of a low angle normal fault: the Altotiberina fault (Northern Apennines, Italy) system case study

2016 ◽  
Author(s):  
Luigi Vadacca ◽  
Emanuele Casarotti ◽  
Lauro Chiaraluce ◽  
Massimo Cocco
Keyword(s):  
Mechanical Behaviour ◽  
Numerical Models ◽  
Hanging Wall ◽  
Normal Fault ◽  
Active Role ◽  
Northern Apennines ◽  
Fault System ◽  
Tectonically Active ◽  
Main Fault ◽  
Microseismic Activity

Abstract. Geological and seismological observations have been used to parameterize 2D numerical models to simulate the interseismic deformation of a complex extensional fault system located in the Northern Apennines (Italy). The geological system is dominated by the presence of the Altotiberina fault (ATF), a large (60 km along strike) low-angle normal fault 20° dipping in the brittle crust (0–15 km). The ATF is currently interested by a high and constant rate of microseismic activity and no moderate-to-large magnitude earthquakes have been associated to it for the past 1000 years. Modelling results have been compared with GPS data in order to understand the mechanical behaviour of this fault and a suite of minor syn- and antithetic normal fault segments located in the main fault hanging-wall. The results of the simulations demonstrate the active role played by the Altotiberina fault in accommodating the on going tectonic extension in this sector of the chain. The GPS velocity profile constructed through the fault system cannot be explained without including the ATF's contribution to deformation, indicating that this fault although misoriented has to be considered tectonically active and with a creeping behaviour below 5 km of depth. The low angle normal fault also shows a high degree of tectonic coupling with its main antithetic fault (the Gubbio fault) suggesting that creeping along the ATF may control the observed strain localization and the pattern of microseismic activity.

scholarly journals The Amatrice 2016 seismic sequence: a preliminary look at the mainshock and aftershocks distribution

2016 ◽  
Vol 59 ◽  
Author(s):  
Maddalena Michele ◽  
Raffaele Di Stefano ◽  
Lauro Chiaraluce ◽  
Marco Cattaneo ◽  
Pasquale De Gori ◽  
...  
Keyword(s):  
Seismic Activity ◽  
Arrival Time ◽  
Hanging Wall ◽  
Normal Fault ◽  
Horizontal Layer ◽  
Fault System ◽  
Seismic Sequence ◽  
Northern Portion ◽  
Main Fault ◽  
Almost Continuous

<p><em>We relocated the aftershocks of the M<sub>W</sub> 6.0 Amatrice 2016 mainshock by inverting with a non-linear probabilitstic method P- and S-arrival time readings produced and released in near realtime by the analyst seismologists of IGNV on duty in the seismic monitoring room. Earthquakes distribution shows the activation of a normal fault system with a main SW-dipping fault extending from Amatrice to NW of Accumoli village for a total length of 40 km. On the northern portion of the main fault hanging-wall volume, the structure become more complex activating an antithetic fault below the Norcia basin. It is worth nothing that below 8-9 km of depth, the whole fault system has an almost continuous sub-horizontal layer interested by an intense seismic activity, about 2 km</em> thick.</p>

scholarly journals Analysis of the Impact of Fault Mechanism Radiation Patterns on Macroseismic Fields in the Epicentral Area of 1998 and 2004 Krn Mountains Earthquakes (NW Slovenia)

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Andrej Gosar
Keyword(s):  
Site Effects ◽  
Strike Slip ◽  
Radiation Patterns ◽  
Seismogenic Fault ◽  
Active Growth ◽  
Epicentral Area ◽  
Slip Mechanism ◽  
Radiation Amplitude ◽  
The Difference ◽  
The Impact

Two moderate magnitude (Mw = 5.6 and 5.2) earthquakes in Krn Mountains occurred in 1998 and 2004 which had maximum intensity VII-VIII and VI-VII EMS-98, respectively. Comparison of both macroseismic fields showed unexpected differences in the epicentral area which cannot be explained by site effects. Considerably, different distribution of the highest intensities can be noticed with respect to the strike of the seismogenic fault and in some localities even higher intensities have been estimated for the smaller earthquake. Although hypocentres of both earthquakes were only 2 km apart and were located on the same seismogenic Ravne fault, their focal mechanisms showed a slight difference: almost pure dextral strike-slip for the first event and a strike-slip with small reverse component on a steep fault plane for the second one. Seismotectonically the difference is explained as an active growth of the Ravne fault at its NW end. The radiation patterns of both events were studied to explain their possible impact on the observed variations in macroseismic fields and damage distribution. Radiation amplitude lobes were computed for three orthogonal directions: radial P, SV, and SH. The highest intensities of both earthquakes were systematically observed in directions of four (1998) or two (2004) large amplitude lobes in SH component (which corresponds mainly to Love waves), which have significantly different orientation for both events. On the other hand, radial P direction, which is almost purely symmetrical for the strike-slip mechanism of 1998 event, showed for the 2004 event that its small reverse component of movement has resulted in a very pronounced amplitude lobe in SW direction where two settlements are located which expressed higher intensities in the case of the 2004 event with respect to the 1998 one. Although both macroseismic fields are very complex due to influences of multiple earthquakes, retrofitting activity after 1998, site effects, and sparse distribution of settlements, unusual differences in observed intensities can be explained with different radiation patterns.

Complex Slip Distribution of the 2021 Mw 7.4 Maduo, China, Earthquake: An Event Occurring on the Slowly Slipping Fault

2021 ◽  
Author(s):  
Rumeng Guo ◽  
Hongfeng Yang ◽  
Yu Li ◽  
Yong Zheng ◽  
Lupeng Zhang
Keyword(s):  
Slip Rate ◽  
Slip Distribution ◽  
Seismic Gap ◽  
Seismogenic Fault ◽  
Coseismic Slip ◽  
Slip Rates ◽  
Kunlun Mountain ◽  
Coulomb Failure ◽  
Main Fault ◽  
Large Earthquakes

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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