Lateral propagation of the surface trace of the South Alkyonides normal fault segment, central Greece: its impact on models of fault growth and displacement–length relationships

1999 ◽  
Vol 21 (6) ◽  
pp. 635-652 ◽  
Author(s):  
Nigel C Morewood ◽  
Gerald P Roberts
Keyword(s):  
Normal Fault ◽  
The South ◽  
Fault Segment ◽  
Central Greece ◽  
Fault Growth ◽  
Lateral Propagation

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 A snapshot of the earliest stages of normal fault development

2021 ◽  
Author(s):  
Ahmed Alghuraybi ◽  
Rebecca Bell ◽  
Chris Jackson
Keyword(s):  
Seismic Reflection ◽  
Spatial Scales ◽  
Normal Fault ◽  
Normal Faults ◽  
3D Seismic ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Temporal And Spatial ◽  
Fault Growth ◽  
Lateral Propagation

Despite decades of study, models for the growth of normal faults lack a temporal framework within which to understand how these structures accumulate displacement and lengthen through time. Here, we use borehole and high-quality 3D seismic reflection data from offshore Norway to quantify the lateral (0.2-1.8 mmyr-1) and vertical (0.004-0.02 mmyr-1) propagation rates (averaged over 12-44 Myr) for several long (up to 43 km), moderate displacement (up to 225 m) layer-bound faults that we argue provide a unique, essentially ‘fossilised’ snapshot of the earliest stage of fault growth. We show that lateral propagation rates are 90 times faster than displacement rates during the initial 25% of their lifespan suggesting that these faults lengthened much more rapidly than they accrued displacement. Although these faults have slow displacement rates compared with data compiled from 30 previous studies, they have comparable lateral propagation rates. This suggests that the unusual lateral propagation to displacement rate ratio is likely due to fault maturity, which highlights a need to document both displacement and lateral propagation rates to further our understanding of how faults evolve across various temporal and spatial scales.

scholarly journals Nonlinear fault damage zone scaling revealed through analog modeling

Geology ◽  
2021 ◽  
Author(s):  
Sylvain Mayolle ◽  
Roger Soliva ◽  
Stéphane Dominguez ◽  
Christopher Wibberley ◽  
Yannick Caniven
Keyword(s):  
Failure Modes ◽  
Damage Zone ◽  
Normal Fault ◽  
Fault Segment ◽  
Mechanical Unit ◽  
Analog Modeling ◽  
Fault Damage Zone ◽  
Fault Growth ◽  
Fault Displacement ◽  
Zone Growth

Fault damage zones strongly influence fluid flow and seismogenic behavior of faults and are thought to scale linearly with fault displacement until reaching a threshold thickness. Using analog modeling with different frictional layer thicknesses, we investigate damage zone dynamic evolution during normal fault growth. We show that experimental damage zone growth with displacement is not linear but progressively tends toward a threshold thickness, being larger in the thicker models. This threshold thickness increases significantly at fault segment relay zones. As the thickness threshold is approached, the failure mode progressively transitions from dilational shear to isochoric shear. This process affects the whole layer thickness and develops as a consequence of fault segment linkage as inferred in nature when the fault matures. These findings suggest that fault damage zone widths are limited both by different scales of mechanical unit thickness and the evolution of failure modes, ultimately controlled in nature by lithology and deformation conditions.

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 .

Influence of normal fault growth and linkage on the evolution of a rift basin: A case from the Gaoyou depression of the Subei Basin, eastern China

AAPG Bulletin ◽  
2017 ◽  
Vol 101 (02) ◽  
pp. 265-288 ◽  
Author(s):  
Yin Liu ◽  
Qinghua Chen ◽  
Xi Wang ◽  
Kai Hu ◽  
Shaolei Cao ◽  
...  
Keyword(s):  
Eastern China ◽  
Normal Fault ◽  
Rift Basin ◽  
Fault Growth

scholarly journals Monitoring of the geomagnetic and geoelectric field in two regions of Greece for the detection of earthquake precursors

1997 ◽  
Vol 40 (2) ◽  
Author(s):  
G. Vargemezis ◽  
J. Zlotnicki ◽  
G. Tsokas ◽  
B. C. Papazachos ◽  
E. E. Papadimitriou
Keyword(s):  
Climatic Changes ◽  
Earthquake Precursors ◽  
Geoelectric Field ◽  
The South ◽  
Temperature Changes ◽  
Central Greece ◽  
South Eastern ◽  
Precursory Phenomena ◽  
Of Greece ◽  
High Seismicity

Two magnetotelluric stations have been installed in the South-Eastern Thessaly basin (Central Greece), which have recorded the geomagnetic and geoelectric fields since 1993. The aim is to detect long lasting abnormal changes of the geoelectric field which may be due to impending earthquakes. The geoelectric recordings were checked against the climatic changes such as temperature changes and precipitation and no correlation was observed. Ten anomalies were observed with characteristics similar to seismoelectric signals which have been reported in the literature and thus we can assume that these changes constitute precursory phenomena. The duration of these signals varies from several days to a few weeks. Some of them keep on developing until the occurrence of an earthquake, and others appear like transient changes several days before. The high seismicity of the area where the stations are located creates difficulties in the correlation of the signals with certain shocks.

scholarly journals Contrasting geomorphic and stratigraphic responses to normal fault development during single and multi-phase rifting

2021 ◽  
Author(s):  
Sofia Pechlivanidou ◽  
Anneleen Geurts ◽  
Guillaume Duclaux ◽  
Robert Gawthorpe ◽  
Christos Pennos ◽  
...  
Keyword(s):  
Normal Fault ◽  
Sedimentary Facies ◽  
Surface Processes ◽  
Extension Direction ◽  
Multi Phase ◽  
Fault Growth ◽  
Stratigraphic Evolution ◽  
The Impact ◽  
Topographic Evolution ◽  
Previous Phase

Understanding the impact of tectonics on surface processes and the resultant stratigraphic evolution in multi-phase rifts is challenging, as patterns of erosion and deposition related to older phases of extension are overprinted by the subsequent extensional phases. In this study, we use a one-way coupled numerical modelling approach between a tectonic and a surface processes model to investigate topographic evolution, erosion and basin stratigraphy during single and multi-phase rifting. We compare the results from the single and the multi-phase rift experiments for a 5 Myr period during which they experience equal amounts of extension, but with the multi-phase experiment experiencing fault topography inherited from a previous phase of extension. Our results demonstrate a very dynamic evolution of the drainage network that occurs in response to fault growth and linkage and, to depocentre overfilling and overspilling. However, we observe profound differences between topographic and depocenter development during single and multi-phase rifting with implications for sedimentary facies development. Our quantitative approach, enables us to better understand the impact of changing extension direction on the distribution of sediment source areas and the syn-rift stratigraphic development through time and space.

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