The active tectonic structures along the southern margin of Lesvos Island, related to the seismic activity of July 2017, Aegean Sea, Greece

2021 ◽  
Vol 41 (4) ◽  
Author(s):  
P. Nomikou ◽  
D. Papanikolaou ◽  
D. Lampridou ◽  
M. Blum ◽  
C. Hübscher
Keyword(s):  
Seismic Activity ◽  
Aegean Sea ◽  
Tectonic Structures ◽  
Southern Margin ◽  
Active Tectonic

Morphotectonic analysis along the northern margin of Samos Island, related to the seismic activity of October 2020, Aegean Sea, Greece

2021 ◽  
Author(s):  
Paraskevi Nomikou ◽  
Dimitris Evangelidis ◽  
Dimitris Papanikolaou ◽  
Danai Lampridou ◽  
Dimitris Litsas ◽  
...  
Keyword(s):  
Seismic Activity ◽  
Normal Fault ◽  
Aegean Sea ◽  
The South ◽  
The West ◽  
Northern Margin ◽  
Hydrographic Survey ◽  
Southern Margin ◽  
Eastern Aegean ◽  
Division Line

<p>On October 30<sup>th</sup> 2020 a strong earthquake of magnitude 7.0 occurred north of Samos Island at the Eastern Aegean Sea. This seismic event was another destructive active deformation in the long seismic history of Samos since the ancient times. Preliminary reports focused the seismic epicenter at about 10 km north of Karlovassi, situated at the western part of the Samos E-W trending coastline. The earthquake mechanism corresponds to an E-W normal fault dipping to the north. The activated fault was assumed to be running along the northern margin of Samos Island, which bounds from the south the Samos basin.</p><p>Immediately after the seismic activity and during the aftershock period in December 2020 an hydrographic survey off the northern coastal margin of Samos Island was conducted with R/V NAUTILOS of the Hellenic Navy Hydrographic Service, using the multibeam SeaBat 7160 RESON. The result of the hydrographic survey was a detailed bathymetric map with 15m grid interval and 50m isobaths.  The main morphological aspects of Samos Basin are a 14 km long, 6 km wide and 690 m deep elongated E-W basin developed north of Samos Island.</p><p>The southern margin of the basin is abrupt with morphological slopes of more than 10<sup>o</sup>, following the major E-W normal fault surface, running along the coastal zone, with an overall throw of more than 500m. In contrast, the northern margin of the basin shows a gradual slope increase towards the south from 1<sup>o</sup> to 5<sup>o</sup>. Numerous small canyons trending N-S transversal to the main direction of the Samos coastline are observed along the southern margin, between 600 and 100 m water depth.  These canyons have a length around 2,7 km and width between 100-300 m. Two large submarine landslides with a canyon width of 1,3 km and 0,8 Km, are located north of Karlovasi. The creation of the canyons is probably due to the uplift of Northern Samos Island and their 500 m vertical height difference corresponds to the average fault throw that has controlled the steep slopes of the margin. The orientation of the fault scarp changes at the western Samos coastline from E-W to ENE-WSW facing the neighboring Ikaria Basin, which is developed to the west of Samos Basin. The division line between the Ikaria and Samos basins runs N-S from the northern slopes and coast of the Kerketeas mountain (1443m). The aftershocks of the 30<sup>th</sup> October main shock are limited east of the N-S division line with only a minor activity 15 km to the west within the eastern margin of the Ikaria Basin.</p>

scholarly journals Morphotectonic Analysis along the Northern Margin of Samos Island, Related to the Seismic Activity of October 2020, Aegean Sea, Greece

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 102
Author(s):  
Paraskevi Nomikou ◽  
Dimitris Evangelidis ◽  
Dimitrios Papanikolaou ◽  
Danai Lampridou ◽  
Dimitris Litsas ◽  
...  
Keyword(s):  
Fault Zone ◽  
Seismic Activity ◽  
Volcanic Rocks ◽  
Active Tectonics ◽  
Normal Fault ◽  
Aegean Sea ◽  
Northern Margin ◽  
The North ◽  
Eastern Aegean ◽  
Half Graben

On 30 October 2020, a strong earthquake of magnitude 7.0 occurred north of Samos Island at the Eastern Aegean Sea, whose earthquake mechanism corresponds to an E-W normal fault dipping to the north. During the aftershock period in December 2020, a hydrographic survey off the northern coastal margin of Samos Island was conducted onboard R/V NAFTILOS. The result was a detailed bathymetric map with 15 m grid interval and 50 m isobaths and a morphological slope map. The morphotectonic analysis showed the E-W fault zone running along the coastal zone with 30–50° of slope, forming a half-graben structure. Numerous landslides and canyons trending N-S, transversal to the main direction of the Samos coastline, are observed between 600 and 100 m water depth. The ENE-WSW oriented western Samos coastline forms the SE margin of the neighboring deeper Ikaria Basin. A hummocky relief was detected at the eastern margin of Samos Basin probably representing volcanic rocks. The active tectonics characterized by N-S extension is very different from the Neogene tectonics of Samos Island characterized by NE-SW compression. The mainshock and most of the aftershocks of the October 2020 seismic activity occur on the prolongation of the north dipping E-W fault zone at about 12 km depth.

3D monitoring of active tectonic structures

2003 ◽  
Vol 36 (1-2) ◽  
pp. 103-112 ◽  
Author(s):  
J. Stemberk ◽  
B. Kostak ◽  
V. Vilimek
Keyword(s):  
Tectonic Structures ◽  
Active Tectonic

Fault Distribution, Segmentation and Earthquake Generation Potential of the Philippine Fault in Eastern Mindanao, Philippines

2015 ◽  
Vol 10 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Jeffrey S. Perez ◽  
◽  
Hiroyuki Tsutsumi ◽  
Mabelline T. Cahulogan ◽  
Desiderio P. Cabanlit ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Tectonic Structures ◽  
Active Tectonic ◽  
Earthquake Generation ◽  
Geometric Segmentation ◽  
Fault Distribution

The 1,250-km-long, NNW-trending, arc-parallel Philippine fault, one of the world’s most active tectonic structures, traverses the Philippine archipelago and has been the source of surface-rupturing earthquakes during the last four centuries. In this paper, we will discuss Philippine fault distribution and segmentation in Mindanao Island by integrating detailed fault mapping together with new geological and paleoseismic data and the analysis of historical surface-rupturing earthquakes. Using geometric segmentation criteria, we have identified nine geometric segments separated by discontinuities such as en echelon steps, bends, changes in strike, gaps, steps and bifurcation in the surface trace. Fault segments ranges from 20 to 100 km in length and are capable of generating earthquakes ofMw6.6 toMw7.4. The results of our study have important implications for earthquake generation potential and seismic hazard assessment of the Philippine fault in Mindanao Island.

scholarly journals The northern Thessaly strong earthquakes of March 3 and 4, 2021, and their neotectonic setting

2021 ◽  
Vol 58 ◽  
pp. 222
Author(s):  
Alexandros Chatzipetros ◽  
Spyros Pavlides ◽  
Michael Foumelis ◽  
Sotiris Sboras ◽  
Dimitris Galanakis ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Seismic Hazard Assessment ◽  
Shear Zones ◽  
Normal Faults ◽  
Seismogenic Fault ◽  
Rock Falls ◽  
Tectonic Structures ◽  
Northern Greece ◽  
Stress Changes ◽  
Active Tectonic

A sequence of earthquakes occurred on March 3rd and 4th in Northern Thessaly, northern Greece, associated with previously unknown, blind normal faults within the crystalline Palaeozoic basement of the Pelagonian geotectonic zone. Surficial ground deformation, such as liquefaction phenomena in fluvial plains, as well as soil fissures and rock falls, have been mapped. Geological indications of the unmapped seismic fault, i.e., reactivated shear zones, open cracks, etc., have been identified within the bedrock. Based on geological indications, the main fault projection to the surface could be considered a 15 km NW-SE trending structure and average dip of 45o to the NE. The seismic source of the main shock was modelled, and the Coulomb static stress changes calculated for receiver faults similar to the source. The determination of the active tectonic regime of the region by geodetic data and the well-known faults of NE Thessaly plain are also presented, as well as the revised historical and instrumental seismicity. This earthquake raises new concerns and challenges, revising some established views, such as the status of main stress orientations, the orientation of active tectonic structures, the occurrence of a seismogenic fault in a mountainous massif of crystalline rocks without typical geomorphological expression and the role of blind faults in Seismic Hazard Assessment.

scholarly journals LONG TEMPORAL VARIATION OF SEISMIC PARAMETERS FOR SEISMIC PATTERNS IDENTIFICATION IN GREECE

2004 ◽  
Vol 36 (3) ◽  
pp. 1362
Author(s):  
I. Baskoutas ◽  
G. Panopoulou ◽  
G. Papadopoulos
Keyword(s):  
Temporal Variation ◽  
Seismic Activity ◽  
Time Window ◽  
Energy Parameter ◽  
Aegean Sea ◽  
B Value ◽  
Seismogenic Zone ◽  
Earthquake Catalog ◽  
Estimation Model ◽  
Seismic Parameters

A new approach of detailed spatio-temporal variation analysis of seismic data is proposed by means of FastBEE (Fast estimation of Big Expected Earthquake) aiming at the regional monitoring of seismic activity for premonitory seismic patterns identification. For the investigation of temporal variation, a set of seismic parameters is used, like the logarithm of the number of earthquakes logN, estimates of 6-value obtained by the maximum likelihood estimation model, time clustering of seismic activity AR(t) and of energy released EM, since they can be considered as precursory seismological indicators. Earthquake catalog data, used in this approach, were elaborated in order to construct the time series for each parameter within a time window, large enough, as to guarantee statistical meaningful result. The Hellenic trench-arc region under investigation is chosen in the basis of its seismotectonic characteristics, in relation to the spatial extent of the seismogenic zone. The tools were tested, for long temporal variation features in the Ionian Islands Sea and the North Aegean Sea regions and its successful applicability is presented. The rise of irregularity, along these temporal profiles, was formulated in specific quantitative premonitory seismic pattern. In most of the cases, FastBEE premonitory pattern found shows significant changes from the background values of each parameter. Parameter logN shows a valley form curve, which start to increase before the expected earthquake occurrence, as well as the energy parameter E273, while b-value temporal estimates are forming a mountain shape curve, before the occurrence of a big earthquake. Instead, parameter ÙR(t) present a rapid fluctuation, without any kind of premonitory character

scholarly journals 1881 and 1949 earthquakes at the Chios-Cesme Strait (Aegean Sea) and their relation to tsunamis

2005 ◽  
Vol 5 (5) ◽  
pp. 717-725 ◽  
Author(s):  
Y. Altinok ◽  
B. Alpar ◽  
N. Özer ◽  
C. Gazioglu
Keyword(s):  
Seismic Activity ◽  
Aegean Sea ◽  
Normal Faults ◽  
Natural Phenomena ◽  
Sea Waves ◽  
The South ◽  
Izmir Bay ◽  
Moderate Size ◽  
The North ◽  
Narrow Bays

Abstract. The most earthquake-prone areas in the eastern central Aegean Sea are the Izmir Bay, the Karaburun peninsula and the island of Chios. The level of seismic activity and tsunami potential are influenced by the presence of normal faults around the region. There have been about 20 moderate-size earthquakes from 496 BC to 1949 AD. Among these earthquakes, the ones on the dates 20 March 1389, 13 November 1856, 19/22 January 1866, 3 April 1881 and 23 July 1949 produced tsunamis. The Chios-Cesme earthquake (1881, Mw 6.5) took place in the South of the Cesme strait while the Chios-Karaburun earthquake (1949, Mw 6.7) occurred in the North. The tsunamis caused by the earthquakes affected the coasts of Chios Island and Cesme. These waves are thought to be associated with the earthquakes and co-seismic underwater failures possibly occurred along the coasts of the Chios Island and Karaburun Peninsula or on the complex subaqueous morphology between these lands. Some sea waves or oscillations observed following the aftershocks are believed to be related to other natural phenomena; e.g. the seiches occurred mainly in open-narrow bays as triggered by the earthquakes.

Continuous Real-Time Pipeline Deformation, 3D Positioning and Ground Movement Monitoring Along the Sakhalin-Khabarovsk-Vladivostok Pipeline

2012 ◽  
Author(s):  
Carlos Borda ◽  
Marc Niklès ◽  
Etienne Rochat ◽  
Alexander Grechanov ◽  
Alexander Naumov ◽  
...  
Keyword(s):  
Seismic Activity ◽  
Fiber Optic ◽  
Deformation Monitoring ◽  
Ground Movement ◽  
Mitigation Measures ◽  
Integrity Monitoring ◽  
Accurate Localization ◽  
Critical Areas ◽  
Active Tectonic ◽  
Scalable Monitoring

Operating in remote regions, Russian pipelines not only are subjected to harsh environmental conditions, but also in some of their sections to seismic activity. In order to secure these assets’ integrity, monitoring is mandatory. Due to the long distances to be monitored and to the linear nature of these pipelines, distributed fiber optic sensing is the only solution to provide remote monitoring operation with accurate localization of events. In some cases, it can even take advantage of the telecommunication fibers laid along the pipelines to minimize installation cost. A complete and commercially available solution based on the DITEST Asset Integrity Monitoring (AIM) system combines strain and temperature measurement over 100’s kilometers at meter spatial resolution with dedicated fiber optic cables specifically developed for strain, temperature and ground movement measurement to provide continuous information on any abnormal pipeline behavior, including leak, intrusion, excessive tube deformation and seismic activity. This scalable monitoring solution was adopted to monitor the most critical areas of the Sakhalin-Khabarovsk-Vladivostok pipeline route, which crosses 32 Active Tectonic Faults (ATF) zones. A combination of pipeline deformation monitoring, ground movement detection and leak detection is used to monitor these critical pipeline regions. The early knowledge of abnormal events allows the pipeline owner/operator to take preventive mitigation measures in response to these critical geohazards.

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