Long-Term Morpho-Structural Development of Major Normal Fault Zones, Gran Sasso Area, Central Apennines (Italy)

2021 ◽  
Author(s):  
Hugo Ortner ◽  
Diethard Sanders ◽  
Hannah Pomella

2021 ◽  
Author(s):  
Josipa Majstorović ◽  
Piero Poli

<p>On April 6th 2009 (01:32 UTC) strong earthquake of magnitude M<sub>W</sub>6.1 occurred near the city of L’Aquila in the Abruzzo region in the Central Apennines of Italy. Due to the extensional processes the Abruzzo region is characterized by prominent historical seismicity. However, before the 2009 event the background seismic activity is characterised as sparse and mostly clustered in space and time. The general lack of events, especially small magnitude events before the 2009 event motivated us to study the long-term near-fault seismicity before the large earthquake occurrence. To achieve this we first have to extend the existing catalog. We take into consideration the data from the AQU (42.354, 13.405) station that has been recorded in the city of L’Aquila, near Paganica fault responsible for the 2009 event, during an extensive period of 29-years, 19 years before the event itself. The catalog extension is performed by applying the two-stage convolutional neural network pipeline for earthquake detection and characterisation (epicentral distance and magnitude) using three component signal station waveforms. The algorithm allows us to successfully detect ~800 local events (less than 10 km from the AQU station) in the period 1990-2009. We here present a detailed analysis of this catalog including waveforms characterization to derive new insights about the long term preparation processes(es) occuring before the 2009 M<sub>w</sub>6.1 earthquake.</p>



2006 ◽  
Vol 6 (6) ◽  
pp. 999-1006 ◽  
Author(s):  
Y. Altınok ◽  
B. Alpar

Abstract. The long-term seismicity of the Marmara Sea region in northwestern Turkey is relatively well-recorded. Some large and some of the smaller events are clearly associated with fault zones known to be seismically active, which have distinct morphological expressions and have generated damaging earthquakes before and later. Some less common and moderate size earthquakes have occurred in the vicinity of the Marmara Islands in the west Marmara Sea. This paper presents an extended summary of the most important earthquakes that have occurred in 1265 and 1935 and have since been known as the Marmara Island earthquakes. The informative data and the approaches used have therefore the potential of documenting earthquake ruptures of fault segments and may extend the records kept on earthquakes far before known history, rock falls and abnormal sea waves observed during these events, thus improving hazard evaluations and the fundamental understanding of the process of an earthquake.



2007 ◽  
Vol 44 (10) ◽  
pp. 1157-1180 ◽  
Author(s):  
L. Bonzanigo ◽  
E. Eberhardt ◽  
S. Loew

Slope movements of the deep-seated Campo Vallemaggia landslide in the southern Swiss Alps have been reported for over 200 years. Surface and borehole investigations of the unstable mass reveal an up to 300 m deep complex structure incorporating 800 million cubic metres of disturbed metamorphic rocks divided into blocks along primary fault zones. An average slide velocity of approximately 5 cm/year can be calculated from various monitoring data recorded between 1892 and 1995. Block movements primarily involve mechanisms relating to multiple shear surfaces, but in cases where slide blocks are constrained by other blocks, creep deformations are observed. Borehole investigations revealed the presence of artesian water pressures, which when integrated with inclinometer and surface geodetic data, helped to provide key insights into the underlying instability mechanisms. This paper reports the findings of an extensive mapping, geophysical, and monitoring investigation carried out over a 20 year period. Results from the analysis are presented with respect to the hydromechanical factors controlling the unstable mass, the significance of which were instrumental in resolving conflicts with regards to the slope mitigation measures required to stabilize the slope. In Part II (see companion paper, this issue), the stabilization works performed at Campo Vallemaggia and their effectiveness are presented.



2009 ◽  
Vol 48 (1) ◽  
Author(s):  
A. Caracausi ◽  
F. Italiano ◽  
G. Martinelli ◽  
A. Paonita ◽  
A. Rizzo


2016 ◽  
Vol 50 (1) ◽  
pp. 15 ◽  
Author(s):  
E. Delogkos ◽  
T Manzocchi ◽  
C. Childs ◽  
C. Sachanidis ◽  
T. Barmpas ◽  
...  

Six normal fault zones, with throws ranging from a few meters up to 50 m, were studied within an active, open pit, lignite mine in Ptolemais. Each fault was mapped 20 times over a period of five years because at intervals of ca. 3 months working faces are taken back between 20 and 50 m exposing fresh fault outcrops for mapping.Various resolutions of photographs and structural measurements were imported into a fully georeferenced 3D structural interpretation package, resulting in aseismic scale and outcrop resolution 3D fault volume with outcrop and panoramic photographs acting as the seismic sections in equivalent seismic surveys. Low resolution 3D models for the fault system structure at mine scale and higher-resolution 3D models for the fault zone structure were produced after geological interpretation and they can be used for qualitative and quantitative analysis.





Solid Earth ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 1355-1383 ◽  
Author(s):  
Mahtab Mozafari ◽  
Rudy Swennen ◽  
Fabrizio Balsamo ◽  
Hamdy El Desouky ◽  
Fabrizio Storti ◽  
...  

Abstract. The Lower Jurassic platform and basinal deposits exposed in the Montagna dei Fiori Anticline (Central Apennines, Italy) are pervasively affected by dolomitization. Based on the integration of field work, petrography, and geochemistry, two fault-related dolomitization events were recognized and interpreted as having occurred before and during the Apenninic orogeny. Fluid inclusion analysis indicates moderate to elevated salinity values of 3.5 to 20.5 and 12.8 to 18.6 eq. wt % NaCl in the first and the second event, respectively. The estimated salinities, in combination with δ18O values and 87Sr∕86Sr ratios, suggest significant involvement of evaporitic fluids in both events, most likely derived from the underlying Upper Triassic Burano Formation. In addition, the 87Sr∕86Sr ratios up to 0.70963 suggest the circulation of deep-sourced fluids that interacted with siliciclastic rocks and/or the crystalline basement during the dolomitization events. Two major dolomite types (D1 and D2) were recognized as pertaining to the first event, both postdated by high-amplitude bed-parallel stylolites, supporting a syn-burial pre-layer-parallel shortening dolomitization. A possible geodynamic framework for this dolomitization event is Early Jurassic to Late Jurassic rift-related extensional tectonism. The second dolomitization event (D3, D4, and D5) is characterized by a temperature upturn (up to 105 ∘C) and interpreted as associated with the inflow of hydrothermal fluids, possibly related to major changes in the permeability architecture of faults during early- to syn-thrusting and folding activity. Based on the timing of deformation in the Montagna dei Fiori Anticline, the second dolomitization event likely occurred in Late Miocene to Pliocene times. The findings regarding characteristics and timing of dolomitization here illustrates the long-term controlling role of the evaporitic detachments in the dolomitization process. This study shows that the Mg-rich fluids that were most likely derived from evaporites may prime the tectonically involved successions for repeated dolomitization, and hence the formation of potential reservoirs during sequential tectonic modifications (extensional vs. compressional).



2001 ◽  
Vol 14 (6) ◽  
pp. 321-344 ◽  
Author(s):  
Fabrizio Galadini ◽  
Paolo Messina


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