scholarly journals Inference of a seismic gap from geological data: Thessaly ( Central Greece) as a case study

1995 ◽  
Vol 38 (1) ◽  
Author(s):  
R. Caputo
Keyword(s):  
Late Quaternary ◽  
Active Faults ◽  
Slip Rate ◽  
Morphological Data ◽  
Tectonic Activity ◽  
Seismic Gap ◽  
Microseismic Activity ◽  
Two Sectors

As a result of neotectonic, morphotectonic and seismotectonic research it is now possible to draw detailed maps of the major active faults affecting Thessaly, a large region of continental Greece. For many of these faults, where specific studies have been carried out, the degree of fault activity (i.e. the long-term slip-rate) has been also assigned ranging from 0.05 to 4 mm/yr-l. In the present work, the main morphotectonic features and seismotectonic characteristics of the more important faults are recalled from previous works, while the recent tectonic activity is compared with the seismic activity of the area. The occuuence of both large (M ?x2264; 6.0) and moderate (M ?x2265; 6.0) earthquakes during the present century is concentrated in the southern sector. Earthquakes have been virtually absent in the northern part of the region during the same period. In contrast, according to geological and geomorphological criteria, the recent (Late Quaternary) tectonic evolution of the region and the overall extensional rate do not seem to djffer significantly in the two sectors. Although palaeosejsmological trenches, geodetic surveying and the record of the microseismic activity may enhance our knowledge of this problem, on the basis of available geological (structural and morphological) data, it is likely that the northern sector of Thessaly represents a large seismic gap. The implications on seismic hazard in one of the more populated regions of Greece are also discussed.

scholarly journals VÝZKUM POZDNĚ KVARTÉRNÍ AKTIVITY ZLOMU KOSÍŘE V HORNOMORAVSKÉM ÚVALU ANEB PROČ JE DOBRÉ STUDOVAT SVAHOVINY A SEISMOGRAMY

2016 ◽  
Vol 22 (1-2) ◽  
Author(s):  
Petr Špaček ◽  
Vít Ambrož
Keyword(s):  
Late Pleistocene ◽  
Late Quaternary ◽  
Slip Rate ◽  
Fault Scarp ◽  
Strike Slip ◽  
Tectonic Activity ◽  
Temporary Increase ◽  
Normal Faulting ◽  
Major Fault ◽  
Complex Sequences

Preliminary results of a research into the late Quaternary slip of a major fault in the seismically active Upper Morava Basin are given. Three trenches, up to 6 m deep, were excavated at the foot of the Kosíř Fault scarp near Stařechovice and Čelechovice. The exposed complex sequences of colluvium and loess, now only partly dated by OSL and 14C, is heavily faulted. The faulting is explained by a tectonic slip at the Kosíř Fault and, in the Stařechovice trench, also by simultaneous slope deformations. None of the faults do off set the Holocene topsoil but the youngest of them were clearly active aft er the deposition of the youngest loess and indicate the slip of up to 1.4 m in Late Pleistocene. In Čelechovice trenches the minimum vertical throw of 4 m is indicated for the lower part of the sequence with assumed Late Pleistocene age. The geometry of the deformed zone suggests an oblique normal faulting with significant strike-slip component. The sense of shearing in the horizontal plane was not resolved. Minimum tectonic slip rate of 0.1‒0.3 mm/year in Late Pleistocene is suggested but this must be confi rmed by new dating. Our observations reveal surprisingly young and large deformation which may suggest a temporary increase of tectonic activity during Late Pleistocene.

scholarly journals GPR signature of Quaternary faulting: a study from the Mt. Pollino region, southern Apennines, Italy

2021 ◽  
Author(s):  
Maurizio Ercoli ◽  
Daniele Cirillo ◽  
Cristina Pauselli ◽  
Harry M. Jol ◽  
Francesco Brozzetti
Keyword(s):  
Late Quaternary ◽  
Active Faults ◽  
Normal Fault ◽  
Data Interpretation ◽  
Seismic Gap ◽  
Southern Apennines ◽  
Near Surface ◽  
Radar Images ◽  
Sedimentary Fill ◽  
Continental Basin

Abstract. With the aim of unveiling evidence of Late Quaternary faulting, a series of Ground Penetrating Radar (GPR) profiles were acquired across the Campotenese continental basin (Mt. Pollino region) in the southern Apennines active extensional belt (Italy). A set of forty-nine 300 MHz and 500 MHz GPR profiles, traced nearly perpendicular to a buried normal fault, were acquired and carefully processed through a customized workflow. The data interpretation allowed us to reconstruct a pseudo-3D model depicting the boundary between the Mesozoic bedrock and the sedimentary fill of the basin, which were in close proximity to the fault. Once reviewing and defining the GPR signature of faulting, we highlight in our data how near surface alluvial and colluvial sediments appear to be dislocated by a set of conjugate (west and east-dipping) discontinuities that penetrate inside the underlying Triassic dolostones. Close to the contact between the continental deposits and the bedrock, some buried scarps which offset wedge-shaped deposits are interpreted as coseismic ruptures, subsequently sealed by later deposits. Although the use of pseudo-3D GPR data implies more complexity linking the geophysical features among the radar images, we have reconstructed a reliable subsurface fault pattern, discriminating master faults and a series of secondary splays. We believe our contribution provides an improvement in the characterization of active faults in the study area which falls within the Pollino seismic gap and is considered potentially prone to severe surface faulting. Our aim is for our approach and workflow to be of inspiration for further studies in the region as well as for similar high seismic hazard areas characterized by scarcity of near-surface data.

scholarly journals The Subsurface Geology and Landscape Evolution of the Volturno Coastal Plain, Italy: Interplay between Tectonics and Sea-Level Changes during the Quaternary

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3386
Author(s):  
Giuseppe Corrado ◽  
Sabrina Amodio ◽  
Pietro P. C. Aucelli ◽  
Gerardo Pappone ◽  
Marcello Schiattarella
Keyword(s):  
Cross Sections ◽  
Coastal Plain ◽  
Late Quaternary ◽  
Slip Rate ◽  
Tectonic Activity ◽  
Paleoenvironmental Reconstruction ◽  
Sea Level Changes ◽  
Plan View ◽  
North West ◽  
The North

The Volturno alluvial-coastal plain is a relevant feature of the Tyrrhenian side of southern Italy. Its plan-view squared shape is due to Pliocene-Quaternary block-faulting of the western flank of the south-Apennines chain. On the basis of the stratigraphic analysis of almost 700 borehole logs and new geomorphological survey, an accurate paleoenvironmental reconstruction before and after the Campania Ignimbrite (CI; about 40 ky) eruption is here presented. Tectonics and eustatic forcing have been both taken into account to completely picture the evolution of the coastal plain during Late Quaternary times. The upper Pleistocene-Holocene infill of the Volturno plain has been here re-organized in a new stratigraphic framework, which includes seven depositional units. Structural analysis showed that two sets of faults displaced the CI, so accounting for recent tectonic activity. Yet Late Quaternary tectonics is rather mild, as evidenced by the decametric vertical separations operated by those faults. The average slip rate, which would represent the tectonic subsidence rate of the plain, is about 0.5 mm/year. A grid of cross sections shows the stratigraphic architecture which resulted from interactions among eustatic changes, tectonics and sedimentary input variations. On the basis of boreholes analysis, the trend of the CI roof was reconstructed. An asymmetrical shape of its ancient morphology—with a steeper slope toward the north-west border—and the lack of coincidence between the present course of the Volturno River and the main buried bedrock incision, are significant achievements of this study. Finally, the morpho-evolutionary path of the Volturno plain has been discussed.

scholarly journals The Lavic Lake Fault: A Long-Term Cumulative Slip Analysis via Combined Field Work and Thermal Infrared Hyperspectral Airborne Remote Sensing

2020 ◽  
Vol 12 (21) ◽  
pp. 3586
Author(s):  
Rebecca A. Witkosky ◽  
Joann M. Stock ◽  
David M. Tratt ◽  
Kerry N. Buckland ◽  
Paul M. Adams ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Auxiliary Information ◽  
Slip Rate ◽  
Ground Truth ◽  
Thermal Infrared ◽  
Field Work ◽  
Tectonic Activity ◽  
Geologic Mapping ◽  
Eastern California Shear Zone

The 1999 Hector Mine earthquake ruptured to the surface in eastern California, with >5 m peak right-lateral slip on the Lavic Lake fault. The cumulative offset and geologic slip rate of this fault are not well defined, which inhibits tectonic reconstructions and risk assessment of the Eastern California Shear Zone (ECSZ). With thermal infrared hyperspectral airborne imagery, field data, and auxiliary information from legacy geologic maps, we created lithologic maps of the area using supervised and unsupervised classifications of the remote sensing imagery. We optimized a data processing sequence for supervised classifications, resulting in lithologic maps over a test area with an overall accuracy of 71 ± 1% with respect to ground-truth geologic mapping. Using all of the data and maps, we identified offset bedrock features that yield piercing points along the main Lavic Lake fault and indicate a 1036 +27/−26 m net slip, with 1008 +14/−17 m horizontal and 241 +51/−47 m vertical components. For the contribution from distributed shear, modern off-fault deformation values from another study imply a larger horizontal slip component of 1276 +18/−22 m. Within the constraints, we estimate a geologic slip rate of <4 mm/yr, which does not increase the sum geologic Mojave ECSZ rate to current geodetic values. Our result supports previous suggestions that transient tectonic activity in this area may be responsible for the discrepancy between long-term geologic and present-day geodetic rates.

scholarly journals LATE QUATERNARY AND HOLOCENE FAULTS OF THE NORTHERN GULF OF CORINTH RIFT, CENTRAL GREECE

2017 ◽  
Vol 50 (1) ◽  
pp. 164 ◽  
Author(s):  
S. Valkaniotis ◽  
S. Pavlides
Keyword(s):  
Late Quaternary ◽  
Active Faults ◽  
Geological Mapping ◽  
Tectonic Activity ◽  
Normal Faults ◽  
Central Greece ◽  
The North ◽  
Gulf Of Corinth ◽  
Area Of Study

New results for the recent tectonic activity in the northern part of the Gulf of Corinth rift are presented. Geological mapping and morphotectonic study re populate the area of study with numerous active and possible active faults. The area is dominated by individual and segmented normal faults along with major structures like Marathias and Delphi-Arachova faults. The results are in accordance with recent studies that reveal a more complex and wider structure of Corinth Rift to the north.

Sign in / Sign up

Export Citation Format

Share Document