Slip rate depth distribution for active faults in Central Italy using numerical models

2016 ◽  
Vol 687 ◽  
pp. 232-244 ◽  
Author(s):  
Debora Finocchio ◽  
Salvatore Barba ◽  
Roberto Basili
Keyword(s):  
Depth Distribution ◽  
Numerical Models ◽  
Central Italy ◽  
Active Faults ◽  
Slip Rate

scholarly journals Morphotectonic Evolution of an Alluvial Fan: Results of a Joint Analog and Numerical Modeling Approach

Geosciences ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 412
Author(s):  
Clément Garcia-Estève ◽  
Yannick Caniven ◽  
Rodolphe Cattin ◽  
Stéphane Dominguez ◽  
Romain Sylvain
Keyword(s):  
Numerical Modeling ◽  
Numerical Models ◽  
Active Faults ◽  
Slip Rate ◽  
Suspended Sediments ◽  
Fault Scarp ◽  
Alluvial Fan ◽  
Critical Parameters ◽  
Drainage Network ◽  
Stick Slip

Surface topography results from complex couplings and feedbacks between tectonics and surface processes. We combine analog and numerical modeling, sharing similar geometry and boundary conditions, to assess the topographic evolution of an alluvial fan crossed by an active thrust fault. This joint approach allows the calibration of critical parameters constraining the river deposition–incision laws, such as the settling velocity of suspended sediments, the bed-rock erodibility, or the slope exponent. Comparing analog and numerical models reveals a slope-dependent threshold process, where a critical slope of ca. 0.081 controls the temporal evolution of the drainage network. We only evidence minor topographic differences between stable and stick-slip fault behavior localized along the fault scarp. Although this topographic signature may increase with the slip rate and the return period of slip events, it remains slight compared to the cumulated displacement along the fault scarp. Our results demonstrate that the study of morphology cannot be used alone to study the slip mode of active faults but can be a valuable tool complementing stratigraphic and geodetic observations. In contrast, we underline the significant signature of the distance between the fault and the sediment source, which controls the degree of channels incision and the density of the drainage network.

scholarly journals Rupture-dependent breakdown energy in fault models with thermo-hydro-mechanical processes

2020 ◽  
Author(s):  
Valère Lambert ◽  
Nadia Lapusta
Keyword(s):  
Material Property ◽  
Numerical Models ◽  
Slip Rate ◽  
Shear Cracks ◽  
Dynamic Rupture ◽  
Rupture Dynamics ◽  
Stress Changes ◽  
History Of ◽  
Thermal Pressurization ◽  
Pass Through

Abstract. Substantial insight into earthquake source processes has resulted from considering frictional ruptures analogous to cohesive-zone shear cracks from fracture mechanics. This analogy holds for slip-weakening representations of fault friction that encapsulate the resistance to rupture propagation in the form of breakdown energy, analogous to fracture energy, prescribed in advance as if it were a material property of the fault interface. Here, we use numerical models of earthquake sequences with enhanced weakening due to thermal pressurization of pore fluids to show how accounting for thermo-hydro-mechanical processes during dynamic shear ruptures makes breakdown energy rupture-dependent. We find that local breakdown energy is neither a constant material property nor uniquely defined by the amount of slip attained during rupture, but depends on how that slip is achieved through the history of slip rate and dynamic stress changes during the rupture process. As a consequence, the frictional breakdown energy of the same location along the fault can vary significantly in different earthquake ruptures that pass through. These results suggest the need for re-examining the assumption of pre-determined frictional breakdown energy common in dynamic rupture modeling and for better understanding of the factors that control rupture dynamics in the presence of thermo-hydro-mechanical processes.

scholarly journals Methodology for Earthquake Rupture Rate estimates of fault networks: example for the Western Corinth Rift, Greece

2017 ◽  
Author(s):  
Thomas Chartier ◽  
Oona Scotti ◽  
Hélène Lyon-Caen ◽  
Aurélien Boiselet
Keyword(s):  
Active Faults ◽  
Slip Rate ◽  
Seismic Hazard Assessment ◽  
System Level ◽  
Fault System ◽  
Normal Faults ◽  
Accurate Estimation ◽  
Probabilistic Seismic Hazard Assessment ◽  
Earthquake Rupture ◽  
Multiple Faults

Abstract. Modelling the seismic potential of active faults is a fundamental step of probabilistic seismic hazard assessment (PSHA). An accurate estimation of the rate of earthquakes on the faults is necessary in order to obtain the probability of exceedance of a given ground motion. Most PSHA studies consider faults as independent structures and neglect the possibility of multiple faults or fault segments rupturing simultaneously (Fault to Fault -FtF- ruptures). The latest Californian model (UCERF-3) takes into account this possibility by considering a system level approach rather than an individual fault level approach using the geological , seismological and geodetical information to invert the earthquake rates. In many places of the world seismological and geodetical information long fault networks are often not well constrained. There is therefore a need to propose a methodology relying only on geological information to compute earthquake rate of the faults in the network. In this methodology, similarly to UCERF-3, a simple distance criteria is used to define FtF ruptures and consider single faults or FtF ruptures as an aleatory uncertainty. Rates of earthquakes on faults are then computed following two constraints: the magnitude frequency distribution (MFD) of earthquakes in the fault system as a whole must follow an imposed shape and the rate of earthquakes on each fault is determined by the specific slip-rate of each segment depending on the possible FtF ruptures. The modelled earthquake rates are then confronted to the available independent data (geodetical, seismological and paleoseismological data) in order to weigh different hypothesis explored in a logic tree. The methodology is tested on the Western Corinth Rift, Greece (WCR) where recent advancements have been made in the understanding of the geological slip rates of the complex network of normal faults which are accommodating the ~15 mm/yr North-South extension. Modelling results show that geological, seismological extension rates and paleoseismological rates of earthquakes cannot be reconciled with only single fault rupture scenarios and require hypothesising a large spectrum of possible FtF rupture sets. Furthermore, in order to fit the imposed regional Gutenberg-Richter MFD target, some of the slip along certain faults needs to be accommodated either with interseismic creep or as post-seismic processes. Furthermore, individual fault’s MFDs differ depending on the position of each fault in the system and the possible FtF ruptures associated with the fault. Finally, a comparison of modelled earthquake rupture rates with those deduced from the regional and local earthquake catalogue statistics and local paleosismological data indicates a better fit with the FtF rupture set constructed with a distance criteria based on a 5 km rather than 3 km, suggesting, a high connectivity of faults in the WCR fault system.

scholarly journals Identify and Monitor Growth Faulting Using InSAR over Northern Greater Houston, Texas, USA

2019 ◽  
Vol 11 (12) ◽  
pp. 1498 ◽  
Author(s):  
Feifei Qu ◽  
Zhong Lu ◽  
Jin-Woo Kim ◽  
Weiyu Zheng
Keyword(s):  
Active Faults ◽  
Slip Rate ◽  
Local Deformation ◽  
Spatial Density ◽  
Causal Mechanism ◽  
Montgomery County ◽  
Groundwater Exploitation ◽  
Long Time ◽  
Multi Temporal ◽  
Continuous Mining

Growth faults are widely distributed in the Greater Houston (GH) region of Texas, USA, and the existence of faulting could interrupt groundwater flow and aggravate local deformation. Faulting-induced property damages have become more pronounced over the last few years, necessitating further investigation of these faults. Interferometric synthetic aperture radar (InSAR) has been proved to be an effective way for mapping deformations along and/or across fault traces. However, extracting short-wavelength small-amplitude creep signal (about 10–20 mm/yr) from long time span interferograms is extremely difficult, especially in agricultural or vegetated areas. This study aims to position, map and monitor the rate, extent, and temporal evolution of faulting over GH at the highest spatial density using Multi-temporal InSAR (MTI) technique. The MTI method, which maximizes usable signal and correlation, has the ability to identify and monitor faulting and provide accurate and detailed depiction of active faults. Two neighboring L-band Advanced Land Observing (ALOS) tracks (2007–2011) are utilized in this research. Numerous areas of sharp phase discontinuities have been discerned from MTI-derived velocity map. InSAR measurements allow us to position both previously known faults traces as well as nucleation of new fractures not previously revealed by other ground/space techniques. Faulting damages and surface scarps were evident at most InSAR-mapped fault locations through our site investigations. The newly discovered fault activation appears to be related to excessive groundwater exploitation from the Jasper aquifer in Montgomery County. The continuous mining of groundwater from the Jasper aquifer formed new water-level decline cones over Montgomery County, corroborating the intensity of new fractures. Finally, we elaborate the localized fault activities and evaluate the characteristics of faulting (locking depth and slip rate) through modeling MTI-derived deformation maps. The SW–NE-oriented faults pertain to normal faulting with an average slip rate of 7–13 mm/yr at a shallow locking depth of less than 4 km. Identifying and characterizing active faults through MTI and deformation modeling can provide insights into faulting, its causal mechanism and potential damages to infrastructure over the GH.

scholarly journals Brief communication: Remotely piloted aircraft systems for rapid emergency response: road exposure to rockfall in Villanova di Accumoli (central Italy)

2019 ◽  
Vol 19 (2) ◽  
pp. 325-335 ◽  
Author(s):  
Michele Santangelo ◽  
Massimiliano Alvioli ◽  
Marco Baldo ◽  
Mauro Cardinali ◽  
Daniele Giordan ◽  
...  
Keyword(s):  
Emergency Response ◽  
Numerical Models ◽  
Central Italy ◽  
Slope Angle ◽  
Surface Model ◽  
Protection Measures ◽  
Source Areas ◽  
The Road ◽  
Aircraft Systems ◽  
Remotely Piloted Aircraft

Abstract. The use of remotely piloted aircraft systems (RPASs) in geosciences is often aimed at the acquisition of an image sequence to produce digital models and orthophotographs of the topographic surface. The technology can be applied for rockfall hazard and risk assessment. To study rockfalls, an approach consists in the application of numerical models for the computation of rockfall trajectories. Data required for such simulations include digital terrain models, location of the instability source areas, and the mechanical properties of the terrain. In this article, we present an analysis of the earthquake-triggered rockfall that occurred along the SP18 in Villanova di Accumoli (Lazio, central Italy) during the seismic sequence that started on 24 August 2016. A survey with a multicopter was carried out to obtain a surface model of the terrain and identify and characterize the source areas and other instable blocks in areas not accessible in the field. The investigated area extends for 6500 m2 and was covered by 161 photographs that were used to obtain an orthophoto with a ground resolution of 2.5 cm and a digital surface model with a ground resolution of 20 cm × 20 cm, which was processed and fused with GNSS real-time kinematic data. To obtain a map of potential rockfall trajectories, we run the numerical model STONE, using as origin of the boulders both source areas mapped in the field and pixels with a slope angle above a selected threshold. Results showed that only the part of the road SP18 already affected by the rockfall was exposed to further rockfall impacts. In particular, it was observed that 29.2 % (i.e. 12 123) of the 41 500 simulated trajectories may potentially reach or cross this tract of the road. Based on these data, limited protection measures were suggested. The combined use of RPAS data, fused with ground GPS points, an accurate geomorphological survey, and terrain static and dynamic parameters from the literature allows fast, low-cost, and replicable rockfall numerical modelling useful for emergency response and adoption of proper protection measures.

Active Faulting in Source Region of 2016–2017 Central Italy Event Sequence

2018 ◽  
Vol 34 (4) ◽  
pp. 1557-1583 ◽  
Author(s):  
Fabrizio Galadini ◽  
Emanuela Falcucci ◽  
Stefano Gori ◽  
Paolo Zimmaro ◽  
Daniele Cheloni ◽  
...  
Keyword(s):  
Source Region ◽  
Central Italy ◽  
Active Faults ◽  
Earthquake Sequence ◽  
Fault System ◽  
Fault Plane Solutions ◽  
Moment Tensors ◽  
Central Italy Earthquake ◽  
Finite Fault ◽  
Main Shocks

The Central Italy earthquake sequence produced three main shocks: M6.1 24 August, M5.9 26 October, and M6.5 30 October 2016. Additional M5–5.5 events struck this territory on 18 January 2017 in the Campotosto area. Fault plane solutions for the main shocks exhibit normal faulting (characteristic of crustal extension occurring in the inner central Apennines). Significant evidence, including hypocenter locations, strike and dip angles of the moment tensors, inverted finite fault models (using GPS, interferometric aperture radar, and ground motion data), and surface rupture patterns, all point to the earthquakes having been generated on the Mt. Vettore–Mt. Bove fault system (all three main shocks) and on the Amatrice fault, in the northern sector of the Laga Mountains (portion of 24 August event). The earthquake sequence provides examples of both synthetic and antithetic ruptures on a single fault system (30 October event) and rupture between two faults (24 August event). We describe active faults in the region and their segmentation and present understanding of the potential for linkages between segments (or faults) in the generation of large earthquakes.

Seismic velocity precursors to the 2016 Mw 6.5 Norcia (Italy) earthquake

Geology ◽  
2020 ◽  
Vol 48 (9) ◽  
pp. 924-928 ◽  
Author(s):  
C. Chiarabba ◽  
P. De Gori ◽  
M. Segou ◽  
M. Cattaneo
Keyword(s):  
Seismic Velocity ◽  
Time Windows ◽  
Central Italy ◽  
Active Faults ◽  
Central Italy Earthquake ◽  
Preparatory Phase ◽  
Triggering Mechanisms ◽  
Failure Conditions ◽  
Deformation Patterns

Abstract Earthquakes occur as the result of long-term strain accumulation on active faults and complex transient triggering mechanisms. Although laboratory experiments show accelerating deformation patterns before failure conditions are met, imaging similar preparatory phases in nature remains difficult because it requires dense monitoring in advance. The 2016 Amatrice-Visso-Norcia (central Italy) earthquake cascade, captured by an unprecedented seismic network, provided a unique testing ground to image the preparatory phase of a large event. The crustal volume of the Norcia incipient fault was densely illuminated by seismic rays from more than 13,000 earthquakes that occurred within the 3 mo before the main shock nucleation. We performed seismic tomography in distinct time windows that revealed the precursory changes of elastic wave speed, signaling (1) the final locked state of the fault, and (2) the rapid fault-stiffness alterations near the hypocenter just a few weeks before the event. The results are the first instance where short-lived, hard-to-catch crustal properties shed light on evolving earthquake cascades.

Fault scarps and deformation rates in Lazio–Abruzzo, Central Italy: Comparison between geological fault slip-rate and GPS data

2005 ◽  
Vol 408 (1-4) ◽  
pp. 147-176 ◽  
Author(s):  
Ioannis D. Papanikolaou ◽  
Gerald P. Roberts ◽  
Alessandro M. Michetti
Keyword(s):  
Central Italy ◽  
Slip Rate ◽  
Fault Slip ◽  
Gps Data ◽  
Geological Fault ◽  
Fault Slip Rate ◽  
Fault Scarps

Mouvement post-messinien sur la faille de Nimes; implications pour la sismotectonique de la Provence

2001 ◽  
Vol 172 (6) ◽  
pp. 697-711 ◽  
Author(s):  
Antoine Schlupp ◽  
Georges Clauzon ◽  
Jean-Philippe Avouac
Keyword(s):  
Mediterranean Sea ◽  
Fault Location ◽  
Active Faults ◽  
Slip Rate ◽  
Seismic Profiles ◽  
Seismic Line ◽  
Active Deformation ◽  
The North ◽  
The Mediterranean ◽  
Erosion Surface

Abstract The seismicity of southern France probably results from the convergence between Africa and Europe which proceeds at a rate of approximately 0,8 cm/year at the Provence longitude [Nuvell-DeMets et al., 1990]. The potentially active faults delimit a large panel in the Mesozoic cover. It includes E-W compressive structures (Mont-Ventoux, Montagne de Lure to the north, Luberon, Costes et Trevaresse to the south) and NE left-lateral strike slip (Durance to the east and Nimes, to the west, and possibly the Cevennes Fault) [e.g., Grellet et al., 1993; Sebrier et al., 1997; Lacassin et al., 1998]. The Nimes Fault, which is considered as one of the main faults of southeastern France [Combes, 1984; Grellet et al., 1993; Ghafiri, 1995] is associated with only few and small seismic events, but paleoseismic evidence for larger earthquakes, with magnitudes possibly as large as 6.5, were found on a subsidiary fault near Courthezon [Combes et al., 1993]. Here, we try to quantify fault activity over a longer period of time than that accessible from the usual geomorphic approach, by assessing possible displacement of Messinian markers on the Nimes fault. In the early Miocene a regional erosion surface of Burdigalian age (around-20 Ma) was formed. This surface is still preserved and has not been much deformed west of the Nimes fault. To the east, this surface is only gently folded due to E-W anticlines [Champion, 1999; Champion et al., 2000]. This contrast suggests that the Nimes fault has been active and has accommodated N-S shortening after the abandonment of the Burdigalian erosion surface. The Nimes and Pujaut faults can be followed in the topography between Nimes and Sauveterre where they are generally bounded by outcrops of Mesozoic limestone (fig. 2A-3). To the NE, the Nimes fault can be roughly traced across the Quaternary Rhone alluvium, between Sauveterre and the Mont Ventoux. It is marked by disruption of the continuity of the terrasses of Chateauneuf-du-Pape. The signal is only tenuous and cannot be used to infer precisely the fault location and segmentation but suggests that the faults have been active during the Quaternary. During the Messinian, starting at about -5.95 Ma, the Mediterranean sea level fell by about 1500 m [Clauzon, 1975; Krijgsman et al., 1999; Gautier et al., 1994; Cande et Kent, 1992-1995; Clauzon et al., 1995]. The major tributaries were forced to cut down and formed deep and narrow valleys. The Mediterranean sea rose up to an elevation of +80 m NGF at -5.32 Ma, flooding the canyons, and remained stable until about -3.8 Ma [Vail and Mitchum, 1979; Benson et al., 1991; Cita, 1975; Haq et al., 1987; Hilgen et Langeries, 1993]. After -5.32 Ma the canyons were filled with Pliocene sediments. The canyon formed by the Rhone incision during the Messinian crisis is well documented [Clauzon, 1982; Clauzon et al., 1995; Clauzon et al., 1999; Rubino et al., 2000]. We found evidence for a tributary canyon on an old seismic line ELF M2S8. The canyon strikes E-W between the "Barre de Roquemaure" and "Barre de Caderache" and should cross the Nimes Fault. In order to constrain more tightly its geometry near the Nimes Fault, we have implemented three seismic lines. If we trace the position of the southern border of the canyon using the different profiles and the surface geology, we find that the horizontal offset at the fault cannot be much larger than about 500 meters. In order to image a possible smaller offset we have determined the geometry of the canyon from a microseismic zoning technique [Nakamura, 1989; Duval et al., 1997; Ibs-von Seht M. and Wholenberg, 1999; Sabourault, 1999]. Measurements were conducted at 37 points which were used in complement. The depth to the canyon bottom was determined using the velocities derived from the seismic profiles and was cross-checked from the comparison with geological log at points F1 and F2. The geometry of the southern edge of the Messinian canyon, shows a left-lateral offset of 440 m + or -50 m, which might be taken to reflect post-Messinian fault motion. Assuming that the observed 440 m offset of the Messinian canyon at the Nimes fault is due to fault motion, and that the fault slip rate has not varied significantly since the Messinian crisis, we derive a left-lateral slip rate of 0.06 to 0.09 mm/year. Given that the observed deflection of the flank of the canyon might in part be of non tectonic origin, our study basically places an upper limit of 0.09 mm/yr on the slip rate on the Nimes faults. Such a low slip rate is comparable with estimates obtained on the Durance Fault [Baroux, 2000] and on the E-W folds and thrust faults east of the Nimes faults such as Ventoux-Lure and Alpilles-Costes-Trevaresse [Champion, 1999; Champion et al., 2000]. Although the details of the kinematics scheme of active deformation of Provence remain a matter of discussion, these various faults are probably linked and must have similar slip rates.

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