scholarly journals Geometry, kinematics and rates of deformation in a normal fault segment boundary, central Greece

1997 ◽  
Vol 24 (23) ◽  
pp. 3081-3084 ◽  
Author(s):  
N. C. Morewood ◽  
G. P. Roberts
Keyword(s):  
Normal Fault ◽  
Fault Segment ◽  
Central Greece ◽  
Segment Boundary

The geometry, kinematics and rates of deformation within an en échelon normal fault segment boundary, central Italy

2000 ◽  
Vol 22 (8) ◽  
pp. 1027-1047 ◽  
Author(s):  
Nigel C. Morewood ◽  
Gerald P. Roberts
Keyword(s):  
Central Italy ◽  
Normal Fault ◽  
Fault Segment ◽  
Segment Boundary

scholarly journals Seismic and Geodetic Imaging (DInSAR) Investigation of the March 2021 Strong Earthquake Sequence in Thessaly, Central Greece

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 311
Author(s):  
Gerassimos A. Papadopoulos ◽  
Apostolos Agalos ◽  
Andreas Karavias ◽  
Ioanna Triantafyllou ◽  
Issaak Parcharidis ◽  
...  
Keyword(s):  
Moment Tensor ◽  
Normal Fault ◽  
Surface Subsidence ◽  
Ground Subsidence ◽  
Fault Models ◽  
Strong Earthquakes ◽  
Fault Segment ◽  
Central Greece ◽  
Seismic Slip ◽  
Instrumental Period

Three strong earthquakes ruptured the northwest Thessaly area, Central Greece, on the 3, 4 and 12 March 2021. Since the area did not rupture by strong earthquakes in the instrumental period of seismicity, it is of great interest to understand the seismotectonics and source properties of these earthquakes. We combined relocated hypocenters, inversions of teleseismic P-waveforms and of InSAR data, and moment tensor solutions to produce three fault models. The first shock (Mw = 6.3) occurred in a fault segment of strike 314° and dip NE41°. It caused surface subsidence −40 cm and seismic slip 1.2–1.5 m at depth ~10 km. The second earthquake (Mw = 6.2) occurred to the NW on an antithetic subparallel fault segment (strike 123°, dip SW44°). Seismic slip of 1.2 m occurred at depth of ~7 km, while surface subsidence −10 cm was determined. Possibly the same fault was ruptured further to the NW on 12 March (Mw = 5.7, strike 112°, dip SSW42°) that caused ground subsidence −5 cm and seismic slip of 1.0 m at depth ~10 km. We concluded that three blind, unknown and unmapped so far normal fault segments were activated, the entire system of which forms a graben-like structure in the area of northwest Thessaly.

scholarly journals SEGMENTATION AND INTERACTION OF NORMAL FAULTS IN CENTRAL GREECE

2017 ◽  
Vol 43 (1) ◽  
pp. 428 ◽  
Author(s):  
S. Kokkalas
Keyword(s):  
Scaling Laws ◽  
Normal Fault ◽  
Fault Zones ◽  
Segment Length ◽  
Normal Faults ◽  
Mechanical Interaction ◽  
Fault Segment ◽  
Central Greece ◽  
Fault Length ◽  
Radial Propagation

The aim of this study is to improve our understanding on the mechanical interaction and linkage process between normal fault segments. Faults grow by the process of radial propagation and the linkage of segments, as strain increases, evolving to large fault systems. For this purpose we conducted a combined field and photogeological study on two major segmented fault zones in Central Greece, the Atalanti and Arkitsa fault zones. This approach includes effects of fault size and spatial distribution, scaling laws and footwall-hanginwall topography. Throw distribution and the geometry of the segmented fault arrays were analyzed in order to investigate the complexity of fault zones, the fault linkage process and the geometric characteristics of the relay zones formed between individual segments. The correlation of fault throw with fault length (D-L) and the ratios of overlap-separation (OL-S), separation-fault segment length (S-L) and relay displacement vs. separation (Dr-S) were examined in order to give an insight for fault segment interaction and linkage .

Spatial distribution and evolution of fault-segment boundary types in rift systems: observations from experimental clay models

2016 ◽  
Vol 439 (1) ◽  
pp. 79-107 ◽  
Author(s):  
P. S. Whipp ◽  
C. A.-L. Jackson ◽  
R. W. Schlische ◽  
M. O. Withjack ◽  
R. L. Gawthorpe
Keyword(s):  
Spatial Distribution ◽  
Fault Segment ◽  
Segment Boundary

scholarly journals The Traverse Ridge Paleoseismic Site and Ruptures Crossing the Boundary Between the Provo and Salt Lake City Segments of the Wasatch Fault Zone, Utah, United States

2021 ◽  
Vol 9 ◽  
Author(s):  
Nathan A. Toké ◽  
Joseph Phillips ◽  
Christopher Langevin ◽  
Emily Kleber ◽  
Christopher B. DuRoss ◽  
...  
Keyword(s):  
Fault Zone ◽  
Urban Areas ◽  
Salt Lake ◽  
Salt Lake City ◽  
The Holocene ◽  
Fault Segment ◽  
Segment Boundary ◽  
Lake City ◽  
Fault Trace ◽  
Wasatch Fault

How structural segment boundaries modulate earthquake behavior is an important scientific and societal question, especially for the Wasatch fault zone (WFZ) where urban areas lie along multiple fault segments. The extent to which segment boundaries arrest ruptures, host moderate magnitude earthquakes, or transmit ruptures to adjacent fault segments is critical for understanding seismic hazard. To help address this outstanding issue, we conducted a paleoseismic investigation at the Traverse Ridge paleoseismic site (TR site) along the ∼7-km-long Fort Canyon segment boundary, which links the Provo (59 km) and Salt Lake City (40 km) segments of the WFZ. At the TR site, we logged two trenches which were cut across sub-parallel traces of the fault, separated by ∼175 m. Evidence from these exposures leads us to infer that at least 3 to 4 earthquakes have ruptured across the segment boundary in the Holocene. Radiocarbon dating of soil material developed below and above fault scarp colluvial packages and within a filled fissure constrains the age of the events. The most recent event ruptured the southern fault trace between 0.2 and 0.4 ka, the penultimate event ruptured the northern fault trace between 0.6 and 3.4 ka, and two prior events occurred between 1.4 and 6.2 ka (on the southern fault trace) and 7.2 and 8.1 ka (northern fault trace). Colluvial wedge heights of these events ranged from 0.7 to 1.2 m, indicating the segment boundary experiences surface ruptures with more than 1 m of vertical displacement. Given these estimates, we infer that these events were greater than Mw 6.7, with rupture extending across the entire segment boundary and portions of one or both adjacent fault segments. The Holocene recurrence of events at the TR site is lower than the closest paleoseismic sites at the adjacent fault segment endpoints. The contrasts in recurrence rates observed within 15 km of the Fort Canyon fault segment boundary may be explained conceptually by a leaky segment boundary model which permits spillover events, ruptures centered on the segment boundary, and segmented ruptures. The TR site demonstrates the utility of paleoseismology within segment boundaries which, through corroboration of displacement data, can demonstrate rupture connectivity between fault segments and test the validity of rupture models.

scholarly journals Numerical analysis of interseismic, coseismic and postseismic phases for normal and reverse faulting earthquakes in Italy

2020 ◽  
Author(s):  
Matteo Albano ◽  
Salvatore Barba ◽  
Christian Bignami ◽  
Eugenio Carminati ◽  
Carlo Doglioni ◽  
...  
Keyword(s):  
Seismic Waves ◽  
Hanging Wall ◽  
Normal Fault ◽  
Ground Subsidence ◽  
Reverse Fault ◽  
Fault Segment ◽  
Elastic Load ◽  
Reverse Faulting ◽  
Common Framework ◽  
Postseismic Relaxation

Summary The preparation, initiation, and occurrence dynamics of earthquakes in Italy are governed by several frequently unknown physical mechanisms and parameters. Understanding these mechanisms is crucial for developing new techniques and approaches for earthquake monitoring and hazard assessments. Here, we develop a first-order numerical model simulating quasi-static crustal interseismic loading, coseismic brittle episodic dislocations, and postseismic relaxation for extensional and compressional earthquakes in Italy based on a common framework of lithostatic and tectonic forces. Our model includes an upper crust, where the fault is locked, and a deep crust, where the fault experiences steady shear. The results indicate that during the interseismic phase, the contrasting behavior between the upper locked fault segment and lower creeping fault segment generates a stretched volume at depth in the hanging wall via extensional tectonics while a contracted volume forms via compressional tectonics. The interseismic stress and strain gradients invert at the coseismic stage, with the interseismic dilated volume contracting during the coseismic stage, and vice versa. Moreover, interseismic stress gradients promote coseismic gravitational subsidence of the hanging wall for normal fault earthquakes and elastic uplift for reverse fault earthquakes. Finally, the postseismic relaxation is characterized by further ground subsidence and uplift for normal and reverse faulting earthquakes, respectively, which is consistent with the faulting style. The fault is the passive feature, with slipping generating the seismic waves, whereas the energy activating the movement is stored mostly in the hanging wall volume. The main source of energy for normal faulting and thrust is provided by the lithostatic load and elastic load, respectively.

scholarly journals The Bilila-Mtakataka fault in Malaŵi: An active, 100-km long, normal fault segment in thick seismogenic crust

Tectonics ◽  
1997 ◽  
Vol 16 (1) ◽  
pp. 137-150 ◽  
Author(s):  
James Jackson ◽  
Tom Blenkinsop
Keyword(s):  
Normal Fault ◽  
Fault Segment

Structural analysis and fault segment boundary identification along the Hurricane fault in southwestern Utah

1996 ◽  
Vol 18 (8) ◽  
pp. 1017-1029 ◽  
Author(s):  
Meg E. Stewart ◽  
Wanda J. Taylor
Keyword(s):  
Structural Analysis ◽  
Fault Segment ◽  
Segment Boundary ◽  
Boundary Identification
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