Multidisciplinary analyses for mapping and evaluating kinematics and stress/strain field at active faults and fissures at NE Rift, Mt Etna (Italy)

2021 ◽  
Author(s):  
Susanna Falsaperla ◽  
Alessandro Tibaldi ◽  
Noemi Corti ◽  
Emanuela De Beni ◽  
Fabio L. Bonali ◽  
...  
Keyword(s):  
Active Faults ◽  
Normal Fault ◽  
Structural Data ◽  
Field Work ◽  
Normal Faults ◽  
Extension Rate ◽  
Mt Etna ◽  
Hazardous Zone ◽  
Eruptive Fissures ◽  
Ne Rift

<p>Strategies for disaster risk reduction in volcanic areas are mostly driven by multidisciplinary analyses, which offer effective and complementary information on complex geomorphological and volcano-tectonic environments. For example, quantification of the offset at active faults and fissures is of paramount importance to shed light on the kinematics of zones prone to deformation and/or seismic activity. This provides key information for the assessment of seismic hazard, but also for the identification of conditions that may favor magma uprising and opening of eruptive fissures.</p><p>Here we present the results of a study encompassing detailed geological, structural and seismological observations focusing on part of the NE Rift at Etna volcano (Italy). The area is situated at an elevation ranging between 2700 and 1900 m a.s.l. where harsh meteorological conditions and difficult logistics render classical field work a troublesome issue. In order to bypass these difficulties, high-resolution (2.8 cm) UAV survey has been recently completed. The survey highlights the presence of 250 extension fractures, 20 normal fault segments, and 54 eruptive fissures. The study allows us to quantify the kinematics at extensional fractures and normal faults, obtaining an extension rate of 1.9 cm/yr for the last 406 yr. With a total of 432 structural data collected by UAV along with SfM photogrammetry, this work also demonstrates the suitability of the application of such surveys for the monitoring of hazardous zone.</p>

Massive data collection in volcanic areas owing to photogrammetry-derived models: a key example from the NE Rift, Mt Etna (Italy).

2021 ◽  
Author(s):  
Emanuela De Beni ◽  
Alessandro Tibaldi ◽  
Noemi Corti ◽  
Fabio L. Bonali ◽  
Susanna Falsaperla ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Normal Fault ◽  
Weather Conditions ◽  
3D Models ◽  
Point Of View ◽  
Normal Faults ◽  
Extension Rate ◽  
Strong Wind ◽  
Mt Etna ◽  
Ne Rift

<p>The collection of a conspicuous amount of data in volcanic areas is a key for a deeper understanding of the relationships between faulting, diking and superficial volcanic processes. A way to quickly collect huge amounts of data is to analyse photogrammetry-derived models (Digital surface models, orthomosaics and 3D models) using Unmanned Aerial Vehicles (UAVs) to collect all necessary pictures obtaining final models with a texture ground resolution up to 2-3 cm/pix.</p><p>In this work, we describe our approach to build up models of a broad area located in the NE Rift of Mt. Etna, which is affected by continuous ground deformation linked to gravity sliding of the eastern flank of the volcano and dyke injection. The area is characterized by the presence of eruptive craters and fissures, extension fractures, and normal faults, as well as by historical lava flows. The goal was to quantify the kinematics at extensional fractures and normal faults, integrating the latter with seismological data to reconstruct the stress field acting in this peculiar sector of the volcano. By the point of view of UAV surveying, the test area is challenging since it is located at an altitude ranging between 2700 and 1900 m a.s.l., and it is affected by extreme weather conditions, like a strong wind. Resulting models, in the form of DSM and orthomosaic, are characterised by a resolution of 11.86 and 2.97 cm/pix, respectively, obtained from the elaboration of 4018 photos and covering an area of 2.2 km<sup>2</sup>. Thanks to these models, we recognized the presence of 20 normal fault segments, 250 extension fractures, and 54 single eruptive fissures. Considering all the above mention data, we quantified the kinematics at extensional fractures and normal faults, obtaining an extension rate of 1.9 cm/yr for the last 406 yr.</p>

scholarly journals Mapping and evaluating kinematics and the stress and strain field at active faults and fissures: a comparison between field and drone data at the NE rift, Mt Etna (Italy)

Solid Earth ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 801-816
Author(s):  
Alessandro Tibaldi ◽  
Noemi Corti ◽  
Emanuela De Beni ◽  
Fabio Luca Bonali ◽  
Susanna Falsaperla ◽  
...  
Keyword(s):  
Stress Field ◽  
Best Practice ◽  
Ground Deformation ◽  
Active Faults ◽  
Fault System ◽  
Normal Faults ◽  
Extension Rate ◽  
Eastern Flank ◽  
Mt Etna ◽  
Ne Rift

Abstract. We collected drone data to quantify the kinematics at extensional fractures and normal faults, integrated this information with seismological data to reconstruct the stress field, and critically compared the results with previous fieldwork to assess the best practice. As a key site, we analyzed a sector of the northeast rift of Mt Etna, an area affected by continuous ground deformation linked to gravity sliding of the volcano's eastern flank and dike injections. The studied sector is characterized also by the existence of eruptive craters and fissures and lava flows. This work shows that this rift segment is affected by a series of NNE- to NE-striking, parallel extensional fractures characterized by an opening mode along an average N105.7∘ vector. The stress field is characterized by a σHmin trending northwest–southeast. Normal faults strike parallel to the extensional fractures. The extensional strain obtained by cumulating the net offset at extensional fractures with the fault heave gives a stretching ratio of 1.003 in the northeastern part of the study area and 1.005 in the southwestern part. Given a maximum age of 1614 CE for the offset lavas, we obtained an extension rate of 1.9 cm yr−1 for the last 406 years. This value is consistent with the slip along the Pernicana Fault system, confirming that the NE rift structures accommodate the sliding of the eastern flank of the volcano.

scholarly journals Mapping and evaluating kinematics and stress/strain field at active faults and fissures: a comparison between field and drone data at NE Rift, Mt Etna (Italy)

2021 ◽  
Author(s):  
Alessandro Tibaldi ◽  
Noemi Corti ◽  
Emanuela De Beni ◽  
Fabio Luca Bonali ◽  
Susanna Falsaperla ◽  
...  
Keyword(s):  
Stress Field ◽  
Best Practice ◽  
Ground Deformation ◽  
Active Faults ◽  
Normal Faults ◽  
Extension Rate ◽  
North East ◽  
The North ◽  
Mt Etna ◽  
Dyke Injection

Abstract. We collected drone data to quantify the kinematics at extensional fractures and normal faults, integrated this information with seismological data to reconstruct the stress field, and critically compared the results with previous fieldwork to assess the best practice. As key site, we analysed a sector of the North-East Rift of Mt Etna, an area affected by continuous ground deformation linked to gravity sliding of the volcano's eastern flank and dyke injection. The studied sector is characterized also by the existence of eruptive craters and fissures and lava flows. This work shows that this rift segment is affected by a series of NE-striking, parallel extensional fractures characterized by an opening mode along an average N105.7° vector. Normal faults strike parallel to the extensional fractures, although they tend to bend slightly when crossing topographic highs corresponding to pyroclastic cones. The extensional strain obtained by cumulating the net offset at extensional fractures with the fault heave gives a stretching ratio of 1.003 in the northeastern part of the study area and 1.005 in the southwestern part. Given a maximum age of 1614 yr AD for the offset lavas, we obtained an extension rate of 1.9 cm/yr for the last 406 yr. The stress field is characterised by a σHmin trending NW-SE. Results indicate that Structure-from-Motion photogrammetry applied to drone surveys allows to collect large amounts of data with a resolution of 2–3 cm, a detail comparable to field surveys. In the same amount of time, drone survey can allow to collect more data than classical fieldwork, especially in logistically difficult rough terrains.

scholarly journals Potentially active normal faulting zone identified in the eastern margin of Palu City, Central Sulawesi, Indonesia

2021 ◽  
Vol 873 (1) ◽  
pp. 012071
Author(s):  
Anggraini Rizkita Puji ◽  
Mudrik Rahmawan Daryono ◽  
Danny Hilman Natawidjaja
Keyword(s):  
Active Faults ◽  
Digital Terrain Model ◽  
Slip Rate ◽  
Normal Fault ◽  
Provincial Government ◽  
Economic Losses ◽  
Normal Faults ◽  
Normal Faulting ◽  
Eastern Margin ◽  
Central Sulawesi

Abstract The 2018 Mw 7.5 earthquake in Palu, Central Sulawesi, resulting in ~2,000 fatalities and estimated economic losses of ~22.8 trillion Indonesian Rupiah, according to the report of BAPPENAS and Central Sulawesi Provincial-Government. Therefore, it is necessary to prevent similar disaster in the future by further detailed studies of any other potential sources that are capable of generating such hazards. Palu City is in the vast depression valley bordered by mountains in its eastern and western margins. The 2018 earthquake source is the Palukoro Fault, which runs through the western margin of onshore Palu Valley then continued under the bay. Along the eastern margin of the valley, we also identified a wide zone of many potentially active faults strands orienting N-S and NW-SE, showing predominantly normal faulting. These faults are observed from their normal fault scarps as inspected from Light Detection and Ranging Digital Terrain Model (LiDAR DTM) data with 90-cm resolution and field ground checks. The faults deformed the old terrace sediments (Late Pleistocene, ~125 kya), but it is unclear whether they also cut the Holocene young alluvial like the ruptured fault of 2018 event. Further paleoseismology investigation is then necessary to obtain further information about these potentially-active normal faults, including their slip-rate and the past ruptures.

Faults distribution and seismogenic potential in the Calabrian back-arc domain, SE Tyrrhenian Sea

2020 ◽  
Author(s):  
Camilla Palmiotto ◽  
Maria Filomena Loreto ◽  
Francesco Muto ◽  
Valentina Ferrante ◽  
Franco Pettenati ◽  
...  
Keyword(s):  
Active Faults ◽  
Normal Fault ◽  
Historical Seismicity ◽  
Normal Faults ◽  
Transitional Region ◽  
Tyrrhenian Sea ◽  
Seismic Profiles ◽  
Offshore Area ◽  
Fault Systems ◽  
Back Arc

<p>The Western Calabrian margin (Italy) is the most active segment of the Apennine back-arc system, formed in response to the slow Africa – Eurasia convergence. The offshore area represents the transitional region between the arc and the back-arc: it is affected by several fault systems, most of them able to trigger highly destructive earthquakes. Indeed, the Calabria and its western offshore are characterized by the highest seismic moment release of the entire Apennines, also evidenced by historical seismicity catalogue, the most accurate over the world. During last decades, scientific community invested huge resources in assessment of seismic and tsunami hazards. Furthermore, during last years several local-scale works allowed of improving knowledge of the faults geometry, magmatism, seismogenic and tsunamigenic potential along the western offshore region (Loreto et al., 2017; Brutto et al., 2016; De Ritis et al., 2019). Some active faults, belonging to NE-SW-trending normal fault systems accommodating the inner-arc collapse related to slab-decupling, are also responsible of the most destructive historical sequences, still to be adequately characterized. Using vintage SPARKER 30 Kj acquired in the seventies and recent multichannel seismic profiles together with middle resolution morpho-bathymetric data we produced a new tectonic map of the Calabria back-arc system. Further, we characterized some before-unknown faults and linked them with shallow structures, as ridges and slumps / slides. This area seemingly less populated of faults compared to the peri-Tyrrhenian margin, where several faults belong to different systems, i.e. (i) the rifting system active that allowed the opening of the Tyrrhenian Basin and (ii) the slab-decupling related normal faults system currently active. The comparison with historical and instrumental seismicity allowed us to highlight possible seismic gaps that, if considered, could strongly improve the map of seismogenic potential of the Tyrrhenian back-arc system.</p><p> </p><p>Bibliography</p><p>Brutto, F. et al. (2016). The Neogene-Quaternary geodynamic evolution of the central Calabrian Arc: A case study from the western Catanzaro Trough basin. Journal of Geodynamics, 102, 95-114.</p><p>Loreto, M. F. (2017). Reconstructed seismic and tsunami scenarios of the 1905 Calabria earthquake (SE Tyrrhenian sea) as a tool for geohazard assessment. Engineering geology, 224, 1-14.</p><p>Tripodi, V. et al. (2018). Neogene-Quaternary evolution of the forearc and backarc regions between the Serre and Aspromonte Massifs, Calabria (southern Italy). Marine and Petroleum Geology, 95, 328-343.</p>

scholarly journals The role of basement-involved normal faults in the recent tectonics of western Taiwan

2016 ◽  
Vol 153 (5-6) ◽  
pp. 1166-1191 ◽  
Author(s):  
KENN-MING YANG ◽  
RUEY-JUIN RAU ◽  
HAO-YUN CHANG ◽  
CHING-YUN HSIEH ◽  
HSIN-HSIU TING ◽  
...  
Keyword(s):  
Active Faults ◽  
Foreland Basin ◽  
Normal Fault ◽  
Strike Slip ◽  
Fault Reactivation ◽  
Normal Faults ◽  
Thrust Belt ◽  
Structural Style ◽  
Fold And Thrust Belt ◽  
Recent Tectonics

AbstractIn the foreland area of western Taiwan, some of the pre-orogenic basement-involved normal faults were reactivated during the subsequent compressional tectonics. The main purpose of this paper is to investigate the role played by the pre-existing normal faults in the recent tectonics of western Taiwan. In NW Taiwan, reactivated normal faults with a strike-slip component have developed by linkage of reactivated single pre-existing normal faults in the foreland basin and acted as transverse structures for low-angle thrusts in the outer fold-and-thrust belt. In the later stage of their development, the transverse structures were thrusted and appear underneath the low-angle thrusts or became tear faults in the inner fold-and-thrust belt. In SW Taiwan, where the foreland basin is lacking normal fault reactivation, the pre-existing normal faults passively acted as ramp for the low-angle thrusts in the inner fold-and-thrust belt. Some of the active faults in western Taiwan may also be related to reactivated normal faults with right-lateral slip component. Some main earthquake shocks related to either strike-slip or thrust fault plane solution occurred on reactivated normal faults, implying a relationship between the pre-existing normal fault and the triggering of the recent major earthquakes. Along-strike contrast in structural style of normal fault reactivation gives rise to different characteristics of the deformation front for different parts of the foreland area in western Taiwan. Variations in the degree of normal fault reactivation also provide some insights into the way the crust embedding the pre-existing normal faults deformed in response to orogenic contraction.

scholarly journals Analysis of Palaeogene strike-slip tectonics along the southern East Greenland margin (Sødalen area)

1969 ◽  
Vol 23 ◽  
pp. 65-68 ◽  
Author(s):  
Pierpaolo Guarnieri
Keyword(s):  
Structural Data ◽  
Field Work ◽  
Strike Slip ◽  
Normal Faults ◽  
Large Area ◽  
East Greenland ◽  
Tectonic History ◽  
History Of ◽  
Host Rocks ◽  
Greenland Margin

This paper describes structural data collected during field work in southern East Greenland, a region characterised by a complex tectonic history. Here, 3D photogeology based on aerial and oblique photographs using high-resolution photogrammetry of a 150 km2 area in Sødalen in southern East Greenland shows ESE–WNW-trending faults cross-cutting Paleocene rift structures and flexure-related normal faults. The kinematic analysis highlights oblique and left-lateral strike-slip movements along faults oriented 120°. Strike-slip and dip-slip kinematic indicators on the walls of the chilled contacts between alkaline E–W-oriented dykes and the volcanic host rocks suggest that the faults and dykes formed at the same time, or maybe the faults were re-activated at a later stage. Palaeostress analysis, performed by inversion of fault-slip data, shows the presence of three different tectonic events. Coupling the 3D photogeological tool with structural analysis at key localities is a fundamental way to understand better the tectonic history of such a large area.

scholarly journals Dinaric up-thrusts in the Pliocene evolution of the Central Apennines thrust belt of Italy: the Montagna dei Fiori structure

2021 ◽  
pp. 1-16
Author(s):  
Fernando Calamita ◽  
Paolo Pace ◽  
Vittorio Scisciani ◽  
Fabiana Properzi ◽  
Mirko Francioni
Keyword(s):  
Large Scale ◽  
Quaternary Structure ◽  
Regional Scale ◽  
Normal Fault ◽  
Structural Data ◽  
Normal Faults ◽  
Seismic Reflection Profile ◽  
Thrust Belt ◽  
Central Apennines ◽  
Orogenic Belts

Abstract Several orogenic belts exhibit regional-scale anticlines characterized by prominent faults in their crestal/forelimb zone. These faults are also a common feature in the Neogene fold-and-thrust belt of the Apennines, where they have been contrastingly interpreted as younger-on-older thrust faults, large-scale strike-slip faults, and pre- or syn-thrusting normal faults. In this study, we analysed a NW–SE-trending fault (Montagna dei Fiori Fault) that affects the hinge-zone/forelimb of the Montagna dei Fiori Anticline. This fold is the outermost exposed contractional structure within the Pliocene–Quaternary antiformal stack of the outer Central Apennines. The integration of stratigraphic and structural data collected during a field geological survey enabled us to reconstruct a multiphase reactivation and deformation along the Montagna dei Fiori Fault. From the novel field data, a different interpretation for the evolution of the Montagna dei Fiori Fault is proposed. The fault originated as a Late Cretaceous – middle Miocene, NE-dipping, Dinaric up-thrust and was later reactivated, displaced and rotated during Pliocene Apennine thrusting and related folding, until assuming a present-day SW-dipping attitude with an apparent normal fault character. This newly proposed Dinaric origin of the Montagna dei Fiori structure is compared with an analogous subsurface example of a Palaeogene–Quaternary structure imaged by seismic reflection profile in the Adriatic foreland. The outcome of this combined field and subsurface investigation provides new elements to unravel the complex evolution of the Apennine thrust belt that developed at the expense of a previously deformed foreland, ahead of the advancing Dinaric chain.

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.

Progressive development of the Büyük Menderes Graben based on new data, western Turkey

2009 ◽  
Vol 146 (5) ◽  
pp. 652-673 ◽  
Author(s):  
ÖMER FEYZİ GÜRER ◽  
NURAN SARICA-FILOREAU ◽  
MUZAFFER ÖZBURAN ◽  
ERCAN SANGU ◽  
BÜLENT DOĞAN
Keyword(s):  
Middle Miocene ◽  
Normal Fault ◽  
Structural Data ◽  
Detachment Fault ◽  
Normal Faults ◽  
Tectonic Event ◽  
Alluvial Deposits ◽  
Western Turkey ◽  
Northern Margin ◽  
The North

AbstractOblique and normal fault systems exposed in the Büyük Menderes Graben (BMG) region record two successive and independent complex tectonic events. The first group tectonic event is defined by an E–W extension related to N–S contraction and transpression. This group is responsible for the development of NW- and NE-trending conjugate pairs of oblique faults which controlled Early–Middle Miocene basin formation. Between the Early–Middle Miocene and Plio-Quaternary strata exists an unconformity, indicating a period of folding, uplift and severe erosion associated with N–S shortening. The second group of events was the change in tectonic regime from E–W extension to N–S extension which controlled the formation of the Büyük Menderes Graben by three progressive pulses of deformation. The first pulse of extensional deformation was initially recorded in the region by the exhumation of the deep part of the Menderes Massif (MM) with the development of the E-trending Büyük Menderes Detachment Fault (BMDF). The minimum age of this pulse is constrained by the older Plio-Quaternary fluviatile deposits of the Büyük Menderes Graben that range in age from the Plio-Pleistocene boundary interval to Late Pleistocene. The second pulse, which is marked by the rapid deposition of alluvial deposits, initiated the formation of approximately E–W-trending high-angle normal faults synthetic and antithetic to the Büyük Menderes Detachment Fault, on the northern margin during Holocene times. These faults are interpreted as secondary steeper listric faults that merge with the main Büyük Menderes Detachment Fault at depth. The third pulse was the migration of the Büyük Menderes Graben depocentre to the present day position by diachronous activity of secondary steeper listric faults. These steeper faults are the most seismically active tectonic elements in western Turkey. According to the stratigraphic and structural data, the N–S extension in the Büyük Menderes Graben region produced a progressive deformation phase with different pulses during its Plio-Quaternary evolution, with migration of deformation from the master fault to the hangingwall. The formation of diachronous secondary synthetic and antithetic steeper faults on the upper plate of the Büyük Menderes Detachment Fault, hence the southward migration of the deformation and of the Büyük Menderes Graben depocentre, should be related to the evolution of detachment in the region. The presence of the seismically active splays of secondary faults implies an active detachment system in the region. This young Plio-Quaternary N–S extension in the Büyük Menderes Graben may be attributed to the combined effects of the two continuing processes in Aegean region. The first process is back-arc spreading or probably the roll-back of African slab below the south Aegean Arc, which seems to be responsible for the change in the stress tensor from E–W extension to N–S extension. The second and later event is the southwestward escape of the Anatolian block along its boundary fault, that is, the North Anatolian fault (NAF).

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