scholarly journals Ion microprobe dating of fissure monazite in the Western Alps: insights from the Argentera Massif and the Piemontais and Briançonnais Zones

2020 ◽  
Vol 113 (1) ◽  
Author(s):  
Emmanuelle Ricchi ◽  
Edwin Gnos ◽  
Daniela Rubatto ◽  
Martin John Whitehouse ◽  
Thomas Pettke
Keyword(s):  
High Pressure ◽  
Western Alps ◽  
Strike Slip ◽  
Tectonic Activity ◽  
Ion Microprobe ◽  
Eu Anomaly ◽  
Slip Activity ◽  
Ion Probe ◽  
Anticlockwise Rotation ◽  
Dextral Strike Slip

AbstractIon probe 208Pb/232Th fissure monazite ages from the Argentera External Massif and from the high-pressure units of the Western Alps provide new insights on its Cenozoic tectonic evolution. Hydrothermal monazite crystallizes during cooling/exhumation in Alpine fissures, an environment where monazite is highly susceptible to fluid-mediated dissolution-(re)crystallization. Monazite growth domains visualized by BSE imaging all show a negative Eu anomaly, positive correlation of Sr and Ca and increasing cheralite component (Ca + Th replacing 2REE) with decreasing xenotime (Y) component. The huttonite component (Th + Si replacing REE and P) is very low. Growth domains record crystallization following chemical disequilibrium in a fissure environment, and growing evidence indicates that they register tectonic activity. Fissure monazite ages obtained in this study corroborate previous ages, recording crystallization at ~ 36 Ma, ~ 32–30 Ma, and ~ 25–23 Ma in the high-pressure regions of the Western Alps, interpreted to be respectively related to top-NNW, top-WNW and top-SW thrusting in association with strike-slip faulting. During this latter transpressive phase, younger fissure monazite crystallization is recorded between ~ 20.6 and 14 Ma in the Argentera Massif, interpreted to have occurred in association with dextral strike-slip faulting related to anticlockwise rotation of the Corsica-Sardinia Block. This strike-slip activity is predating orogen-parallel dextral strike-slip movements along and through the internal part of all other External Crystalline Massifs (ECM), starting only at ~ 12 Ma. Our combined compositional and age data for hydrothermal monazite track crystallization related to tectonic activity during unroofing of the Western Alps for over more than 20 million years, offering chronologic insights into how different tectonic blocks were exhumed. The data show that fissures in the high-pressure units formed during greenschist to amphibolite facies retrograde deformation, and later in association with strike-slip faulting.

Ion microprobe dating of fissure monazite in the Western Alps: insights from the Argentera Massif and Piemontais and Briançonnais Zones

2020 ◽  
Author(s):  
Emmanuelle Ricchi ◽  
Edwin Gnos ◽  
Daniela Rubatto ◽  
Thomas Pettke
Keyword(s):  
High Pressure ◽  
Growth Conditions ◽  
Western Alps ◽  
Tectonic Activity ◽  
The South ◽  
The North ◽  
Ion Probe ◽  
North Eastern ◽  
Western Border ◽  
Chemical Studies

<p>Ion probe <sup>208</sup>Pb/<sup>232</sup>Th fissure monazite ages from high pressure regions of the Western Alps and from the Argentera Massif provide new insights on the tectonic evolution of the Western Alps during Cenozoic times. Fissure monazite is a hydrothermal mineral crystallizing during cooling/exhumation in Alpine fissures, an environment where monazite is highly susceptible to fluid-mediated dissolution-(re)crystallization. Fissure monazite ages directly record chemical disequilibrium occurring in a fissure environment, but growing evidences indicate that fissure monazite commonly register tectonic activity. Fissure monazite age domains from this study show that monazite crystallization occurred between ~32-30.5 Ma and ~31.5-30 Ma in the Piémontais and Briançonnais Zone of the High Pressure regions, and between ~17-15 Ma and in the north-eastern border of the Argentera Massif. So far, monazite ages were recorded between ~32-23 Ma and at ~20.5 Ma in the Briançonnais Zone and in the south-western border of the Argentera Massif respectively. Thus the presented dataset corroborate and complement already reported fissure monazite <sup>208</sup>Pb/<sup>232</sup>Th ages from the Western Alps. This new fissure monazite ages compilation supports that Late Oligocene thrusting affected the High Pressure regions of the Western Alps, and that Early and Middle Miocene dextral strike-slips movements respectively affected the south-western and north-eastern margins of the Argentera Massif. Chemical observations provide new hints on fissure monazite growth conditions (e.g. leached host-rock minerals, oxidation conditions) encouraging to pursue chemical studies with a larger dataset on natural fissure monazite to better understand growth conditions under cleft environment.</p>

Miocene to Messinian deformation and hydrothermal activity in a pre-Alpine basement massif of the French western Alps: new U-Th-Pb and argon ages from the Lauzière massif

2010 ◽  
Vol 181 (3) ◽  
pp. 227-241 ◽  
Author(s):  
Dominique Gasquet ◽  
Jean-Michel Bertrand ◽  
Jean-Louis Paquette ◽  
Jérémie Lehmann ◽  
Gueorgui Ratzov ◽  
...  
Keyword(s):  
Late Miocene ◽  
Shear Zones ◽  
Hydrothermal Activity ◽  
Western Alps ◽  
Strike Slip ◽  
Quartz Veins ◽  
The North ◽  
Slip Regime ◽  
Tectonically Active ◽  
Dextral Strike Slip

Abstract U-Pb and Th-Pb dating of monazite from hydrothermal quartz veins (“Alpine veins”) from the Lauzière massif (North Belledonne) together with Ar/Ar ages of adularias from the same veins constrain the age of the last tectono-metamorphic events that affected the External Crystalline Massifs (ECM). Ages obtained are surprisingly young. The study of the structural context of the veins combined with our chronological data, allow us to propose a tectonic scenario of the northern ECM for the 15-5 Ma period, which was poorly documented so far. The quartz veins are of two types: (i) the oldest are poorly mineralized (chlorite and epidote), flat-lying veins. The quartz fibres (= extension direction) are near vertical and seem to be associated with a subvertical dissolution schistosity superimposed upon an early Alpine deformation underlined by “mini-biotite”. They bear a sub-horizontal stretching lineation; (ii) the youngest veins are very rich in various minerals (anatase, rutile, phénacite, meneghinite, beryl, synchysite, ….). They are almost vertical. Their “en echelon” geometry as well as the horizontal attitude of their quartz fibres show a dextral strike-slip regime. Two groups of Th-Pb ages have been obtained: 11 to 10 Ma and 7 to 5 Ma. They were obtained from the most recent veins (vertical veins) sampled in different areas of the massif. The ca. 10 Ma ages are related to veins in the Lauzière granite and its metamorphic country-rocks at about 2 km from the eastern contact of the massif, while the ages of ca. 5 Ma correspond to veins occurring in mylonites along this contact. Adularias provided Ar/Ar ages at ca. 7 Ma. By contrast, a monazite from a vein of the Pelvoux massif (Plan du Lac) yielded a Th-Pb age of 17.6 Ma but in a different structural setting. Except fission track ages, there are very little ages of this range published in the recent literature on the Alps. The latter concern always gold mineralized veins (NE Mont Blanc and SW Lepontine dome). The last compressive tectonic regime dated between 15 and 12 Ma is coeval with (i) the late “Roselend thrust” event, which is recorded in the Mont Blanc by shear-zones with vertical lineation, (ii) the last movements in the basal mylonites of the Swiss Nappes, (iii) the horizontal Alpine veins from the Mont Blanc and Belledonne massifs (with vertical quartz fibres), which are similar to the early veins of the Lauzière. On the contrary, the vertical veins of the Lauzière, dated between 11 and 5 Ma, correspond to a dextral strike slip regime. This suggests that most of the strike-slip tectonics along the ECM took place during two stages (ca. 10 Ma and ca. 7-5 Ma) and not only at 18 Ma as had been proposed previously. Our ages are consistent with the late Miocene-Pliocene overlap of the Digne thrust to the South and to part of the normal movement along the Simplon fault to the North. Thus, all the external crystalline massifs were tectonically active during the late Miocene. This suggests that tectonic events in the external alpine belt may have contributed to some extent to the geodynamical causes of the Messinian crisis.

Up to date geodetic velocity field of the Belledonne region (Western Alps, France)

2021 ◽  
Author(s):  
Estelle Hannouz ◽  
Andrea Walpersdorf ◽  
Christian Sue ◽  
Marguerite Mathey ◽  
Stéphane Baize ◽  
...  
Keyword(s):  
Velocity Field ◽  
Slip Rate ◽  
Western Alps ◽  
Strike Slip ◽  
Double Difference ◽  
Deformation Pattern ◽  
Slip Mechanism ◽  
Area Of Interest ◽  
Gnss Data ◽  
Dextral Strike Slip

<p>       The Belledonne region, located on the western edge of the French Alps, behaves as a deformation transfer zone between the inner part of the western Alps, where geodesy and seismicity show extensional deformation, and its compressional surrounding basin (the Rhône Valley). Seismological and geodetic networks are less dense and younger in the Rhône Valley, which makes it more difficult to characterize its deformation. Nevertheless, these two regions have a moderate historical and instrumental seismicity. A large part of these earthquakes is concentrated on the Belledonne range and accommodated by the active NE–SW Belledonne fault, located at the western foot of this chain. The fault characteristics, such as its connection at depth with surrounding fault systems (e.g. Cléry fault), still need better constraints. The dense seismological network present in the Alpine region has made it possible to highlight its dextral strike-slip kinematics. To complete these observations, we present here an update of the geodetic velocity field around this fault from GNSS data recorded over the last two decades.</p><p>To do so, we first computed daily positions for a total of about 200 stations provided by different European networks (IGS, RENAG, RGP, GAIN, DGFI networks) over a period of 23 years (from 1997 to 2020), by using a double-difference processing with the GAMIT software (Herring et al. 2015). Then, we constrained a velocity field with the Kalman filter GLOBK with respect to the fixed European plate. We finally analyzed the residual motions in our area of interest with respect to stable Europe, as provided by our updated velocity field.</p><p>Across the Belledonne range, our results show a deformation pattern consistent with the dextral strike-slip mechanism observed by the current seismicity. Methodological studies concern the expected decrease of uncertainty on the velocity field thanks to the increase of recordings through time. These tests aim at quantifying the Belledonne fault present-day slip rate, including a well-constrained velocity uncertainty. We also exploit the new 3D velocity field to confirm and precise the local amplitude, in the Belledonne area, of the general uplift of the Alpine belt, as observed by previous geodetic studies.</p>

scholarly journals The role of the 'Zvornik suture' for assessing the number of Neotethyan oceans: Surface - subsurface constraints on the fossil plate margin (Vardar Zone vs. Inner Dinarides)

2020 ◽  
Vol 81 (2) ◽  
pp. 63-86
Author(s):  
Darko Spahic ◽  
Tivadar Gaudenyi
Keyword(s):  
Oceanic Lithosphere ◽  
Ocean Model ◽  
Strike Slip ◽  
Fault System ◽  
The West ◽  
Vardar Zone ◽  
Slip Activity ◽  
Dextral Strike Slip Fault ◽  
Dextral Strike Slip

The balancing exercise of the ?single-ocean model? and reexa - mination of Jurassic paleogeographic conditions and tectonic interaction allowed the reconstruction of the mosaic of independent microplate margins and sutured northwestern Tethyan realm (Vardar Ocean). The overprinted Mesozoic convergent margin referred to as the ?Zvornik suture? was of special interest in the reconstruction of the displaced ophiolite belts of Dinarides and Vardar Zone. The surface?subsurface constraints of these mixed crustal units, in particular the polyphase strike-slip character of the ?Zvornik suture? yields the presence of at least two of Neotethyan basins extrapolated in the vicinity of the northwestern segment of this paleosuture - related fault system. The restoration and synopsis shows a limited capability for obduction-related emplacement of the Vardar oceanic lithosphere (West Vardar Zone) accounting the polyphased strike-slip tectonics. The balancing and the proposed tectonic/paleogeographic recon struction does not exclude obduction, but it shows a limited capability with much shorter across-strike width of the highlydeformed West Vardar ophio lite. The presence of the two distinct autochthonous Tethyan oceans divided by this important dextral strike-slip fault zone is suggested: The Inner Dina ric?(Mirdita?Pindos) Ocean or Dinaric Tethys (identified by the Inner Dinaric Ophiolite Belt) and the Vardar Ocean (identified by the West Vardar Zone). The West Vardar Zone remains to be a subzone of the principal composite Neotethyan suture referred to as the Vardar Zone s.s., whereas the Dinaric Tethys have been (re)incorporated to the area of Dinarides (Adria microplate). The northern segments of these two landlocked basins were on both sides of the Inner Dinaridic continental ridge (referred to as the Drina-Ivanjica block), divided by the protracted strike-slip activity of the ?Zvornik suture?.

Detection of tremors in the Marlborough region and its relationship with the 2016 Mw 7.9 Kaikoura (New Zealand) earthquake

2021 ◽  
Author(s):  
Pierre Romanet ◽  
Florent Aden-Antoniow ◽  
Ryosuke Ando ◽  
Stephen Bannister ◽  
Calum Chamberlain ◽  
...  
Keyword(s):  
New Zealand ◽  
Current Knowledge ◽  
Strike Slip ◽  
Tectonic Activity ◽  
North East ◽  
South West ◽  
Using Data ◽  
Kaikoura Earthquake ◽  
Dextral Strike Slip ◽  
Over Time

<p>Seismic tremor has previously been reported in the Marlborough (New Zealand) region, with detections made using the national GeoNet network. However, because of the sparsity of that network, only 40 tremors were detected using 6 stations. We conducted a similar analysis again, but this time using data from 4 stations from the GeoNet network as well as 16 stations from a local campaign network, bringing the total number of stations to 20. Our new tremor catalog contains 4699 tremors (around 100 times more events than the previous catalog) and spans the period 2013-2019 which include the major 2016 Mw7.9 Kaikoura earthquake. Based on our current knowledge, that makes the Marlborough region the most active region for tremors in New Zealand.</p><p> </p><p>The observed tremor in the region are split into two clusters, separated by a gap of around 20 km. The South-West cluster has an elongated shape in the direction of the upper-plate dextral strike-slip (Hope and Clarence) faults. The occurrence of tremor before the Mw 7.9 Kaikoura earthquake is fairly constant over time. After the earthquake however we observe  a strong acceleration in the rate of tremor, that slowly recovers over time. At the end of the analysis (May 2019), more than 2 years after Kaikoura earthquake, the tremor burst rate has still not recovered to the previous rate before the earthquake. We also observe several episodes of tremor migration, with a migration velocity of around ~50km/day, most of the migration being from South-West to North-East.</p><p> </p><p>This new tremor catalog provides a unique opportunity to better understand possible interaction of a major earthquake with the tremor activity and will help to better understand the local tectonic activity of the Marlborough region.</p><p> </p>

Fluidized Catalytic Cracking Catalyst Microstructure as Determined by A Scanning Ion Microprobe

1990 ◽  
Vol 48 (2) ◽  
pp. 302-303
Author(s):  
J.K. Lampert ◽  
G.S. Koermer ◽  
J.M. Macaoy ◽  
J.M. Chabala ◽  
R. Levi-Setti
Keyword(s):  
Catalytic Cracking ◽  
Secondary Ion Mass Spectrometry ◽  
Fuel Oil ◽  
Ion Microprobe ◽  
Fluidized Catalytic Cracking ◽  
Ion Probe ◽  
Silica Alumina ◽  
Resolution Imaging ◽  
The University ◽  
High Spatial Resolution Imaging

We have used high spatial resolution imaging secondary ion mass spectrometry (SIMS) to differentiate mineralogical phases and to investigate chemical segregations in fluidized catalytic cracking (FCC) catalyst particles. The oil industry relies on heterogeneous catalysis using these catalysts to convert heavy hydrocarbon fractions into high quality gasoline and fuel oil components. Catalyst performance is strongly influenced by catalyst microstructure and composition, with different chemical reactions occurring at specific types of sites within the particle. The zeolitic portions of the particle, where the majority of the oil conversion occurs, can be clearly distinguished from the surrounding silica-alumina matrix in analytical SIMS images.The University of Chicago scanning ion microprobe (SIM) employed in this study has been described previously. For these analyses, the instrument was operated with a 40 keV, 10 pA Ga+ primary ion probe focused to a 30 nm FWHM spot. Elemental SIMS maps were obtained from 10×10 μm2 areas in times not exceeding 524s.

scholarly journals Tectono-Sedimentary Evolution of the Cenozoic Basins in the Eastern External Betic Zone (SE Spain)

Geosciences ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 394
Author(s):  
Manuel Martín-Martín ◽  
Francesco Guerrera ◽  
Mario Tramontana
Keyword(s):  
Strike Slip ◽  
Alluvial Fan ◽  
Tectonic Activity ◽  
Time Interval ◽  
Se Spain ◽  
The Third ◽  
Sedimentary Evolution ◽  
Marine Sedimentation ◽  
Geodynamic Processes ◽  
Early Paleocene

Four main unconformities (1–4) were recognized in the sedimentary record of the Cenozoic basins of the eastern External Betic Zone (SE, Spain). They are located at different stratigraphic levels, as follows: (1) Cretaceous-Paleogene boundary, even if this unconformity was also recorded at the early Paleocene (Murcia sector) and early Eocene (Alicante sector), (2) Eocene-Oligocene boundary, quite synchronous, in the whole considered area, (3) early Burdigalian, quite synchronous (recognized in the Murcia sector) and (4) Middle Tortonian (recognized in Murcia and Alicante sectors). These unconformities correspond to stratigraphic gaps of different temporal extensions and with different controls (tectonic or eustatic), which allowed recognizing minor sedimentary cycles in the Paleocene–Miocene time span. The Cenozoic marine sedimentation started over the oldest unconformity (i.e., the principal one), above the Mesozoic marine deposits. Paleocene-Eocene sedimentation shows numerous tectofacies (such as: turbidites, slumps, olistostromes, mega-olistostromes and pillow-beds) interpreted as related to an early, blind and deep-seated tectonic activity, acting in the more internal subdomains of the External Betic Zone as a result of the geodynamic processes related to the evolution of the westernmost branch of the Tethys. The second unconformity resulted from an Oligocene to Aquitanian sedimentary evolution in the Murcia Sector from marine realms to continental environments. This last time interval is characterized as the previous one by a gentle tectonic activity. On the other hand, the Miocene sedimentation was totally controlled by the development of superficial thrusts and/or strike-slip faults zones, both related to the regional geodynamic evolutionary framework linked to the Mediterranean opening. These strike-slip faults zones created subsidence areas (pull-apart basin-type) and affected the sedimentation lying above the third unconformity. By contrast, the subsidence areas were bounded by structural highs affected by thrusts and folds. After the third unconformity, the Burdigalian-Serravallian sedimentation occurred mainly in shallow- to deep-water marine environments (Tap Fm). During the Late Miocene, after the fourth unconformity, the activation of the strike-slip faults zones caused a shallow marine environment sedimentation in the Murcia sector and a continental (lacustrine and fluvial) deposition in the Alicante sector represented the latter, resulting in alluvial fan deposits. Furthermore, the location of these fans changed over time according to the activation of faults responsible for the tectonic rising of Triassic salt deposits, which fed the fan themselves.

scholarly journals Kinematic partitioning in the Southern Andes (39° S–46° S) inferred from lineament analysis and reassessment of exhumation rates

2021 ◽  
Author(s):  
Paul Leon Göllner ◽  
Jan Oliver Eisermann ◽  
Catalina Balbis ◽  
Ivan A. Petrinovic ◽  
Ulrich Riller
Keyword(s):  
Fault Zone ◽  
Vertical Displacement ◽  
Strike Slip ◽  
Structural Studies ◽  
Southern Andes ◽  
Plate Convergence ◽  
Exhumation Rates ◽  
Lineament Analysis ◽  
Dextral Strike Slip ◽  
Data Call

AbstractThe Southern Andes are often viewed as a classic example for kinematic partitioning of oblique plate convergence into components of continental margin-parallel strike-slip and transverse shortening. In this regard, the Liquiñe-Ofqui Fault Zone, one of Earth’s most prominent intra-arc deformation zones, is believed to be the most important crustal discontinuity in the Southern Andes taking up margin-parallel dextral strike-slip. Recent structural studies, however, are at odds with this simple concept of kinematic partitioning, due to the presence of margin-oblique and a number of other margin-parallel intra-arc deformation zones. However, knowledge on the extent of such zones in the Southern Andes is still limited. Here, we document traces of prominent structural discontinuities (lineaments) from the Southern Andes between 39° S and 46° S. In combination with compiled low-temperature thermochronology data and interpolation of respective exhumation rates, we revisit the issue of kinematic partitioning in the Southern Andes. Exhumation rates are maximal in the central parts of the orogen and discontinuity traces, trending predominantly N–S, WNW–ESE and NE–SW, are distributed across the entire width of the orogen. Notably, discontinuities coincide spatially with large gradients in Neogene exhumation rates and separate crustal domains characterized by uniform exhumation. Collectively, these relationships point to significant components of vertical displacement on these discontinuities, in addition to horizontal displacements known from published structural studies. Our results agree with previously documented Neogene shortening in the Southern Andes and indicate orogen-scale transpression with maximal vertical extrusion of rocks in the center of the transpression zone. The lineament and thermochronology data call into question the traditional view of kinematic partitioning in the Southern Andes, in which deformation is focused on the Liquiñe-Ofqui Fault Zone.

scholarly journals Metasediments Covering Ophiolites in the HP Internal Belt of the Western Alps: Review of Tectono-Stratigraphic Successions and Constraints for the Alpine Evolution

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 411
Author(s):  
Paola Tartarotti ◽  
Silvana Martin ◽  
Andrea Festa ◽  
Gianni Balestro
Keyword(s):  
High Pressure ◽  
Western Alps ◽  
Metamorphic Evolution ◽  
Alpine Orogeny ◽  
Sedimentary Evolution ◽  
Hp Metamorphism ◽  
Tethys Ocean ◽  
Depositional Setting ◽  
Oceanic Rocks ◽  
Outer Band

Ophiolites of the Alpine belt derive from the closure of the Mesozoic Tethys Ocean that was interposed between the palaeo-Europe and palaeo-Adria continental plates. The Alpine orogeny has intensely reworked the oceanic rocks into metaophiolites with various metamorphic imprints. In the Western Alps, metaophiolites and continental-derived units are distributed within two paired bands: An inner band where Alpine subduction-related high-pressure (HP) metamorphism is preserved, and an outer band where blueschist to greenschist facies recrystallisation due to the decompression path prevails. The metaophiolites of the inner band are hugely important not just because they provide records of the prograde tectonic and metamorphic evolution of the Western Alps, but also because they retain the signature of the intra-oceanic tectono-sedimentary evolution. Lithostratigraphic and petrographic criteria applied to metasediments associated with HP metaophiolites reveal the occurrence of distinct tectono-stratigraphic successions including quartzites with marbles, chaotic rock units, and layered calc schists. These successions, although sliced, deformed, and superposed in complex ways during the orogenic stage, preserve remnants of their primary depositional setting constraining the pre-orogenic evolution of the Jurassic Tethys Ocean.

scholarly journals Coseismic fault-slip distribution of the 2019 Ridgecrest Mw6.4 and Mw7.1 earthquakes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yang Gao ◽  
HuRong Duan ◽  
YongZhi Zhang ◽  
JiaYing Chen ◽  
HeTing Jian ◽  
...  
Keyword(s):  
Strike Slip ◽  
Fault Slip ◽  
Slip Distribution ◽  
Synthetic Aperture ◽  
Seismic Events ◽  
Interferometric Synthetic Aperture Radar ◽  
The Past ◽  
Dextral Strike Slip Fault ◽  
Fault Slip Distribution ◽  
Dextral Strike Slip

AbstractThe 2019 Ridgecrest, California seismic sequence, including an Mw6.4 foreshock and Mw7.1 mainshock, represent the largest regional seismic events within the past 20 years. To obtain accurate coseismic fault-slip distribution, we used precise positioning data of small earthquakes from January 2019 to October 2020 to determine the dip parameters of the eight fault geometry, and used the Interferometric Synthetic Aperture Radar (InSAR) data processed by Xu et al. (Seismol Res Lett 91(4):1979–1985, 2020) at UCSD to constrain inversion of the fault-slip distribution of both earthquakes. The results showed that all faults were sinistral strike-slips with minor dip-slip components, exception for dextral strike-slip fault F2. Fault-slip mainly occurred at depths of 0–12 km, with a maximum slip of 3.0 m. The F1 fault contained two slip peaks located at 2 km of fault S4 and 6 km of fault S5 depth, the latter being located directly above the Mw7.1hypocenter. Two slip peaks with maximum slip of 1.5 m located 8 and 20 km from the SW endpoint of the F2 fault were also identified, and the latter corresponds to the Mw6.4 earthquake. We also analyzed the influence of different inversion parameters on the fault slip distribution, and found that the slip momentum smoothing condition was more suitable for the inversion of the earthquakes slip distribution than the stress-drop smoothing condition.

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