scholarly journals Geochemical Characteristics of Soil Gas and Strong Seismic Hazard Potential in the Liupanshan Fault Zone (LPSFZ)

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Huiling Zhou ◽  
Hejun Su ◽  
Hui Zhang ◽  
Chenhua Li ◽  
Dongzheng Ma ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Fault Zone ◽  
Seismic Activity ◽  
Soil Gas ◽  
Seismic Gap ◽  
Strong Earthquakes ◽  
Hazard Potential ◽  
The North ◽  
Soil Gas Radon ◽  
Northern Segment

Eight soil gas measurements were performed in the Liupanshan fault zone (LPSFZ) to observe the concentration and flux of soil gas radon (Rn) and CO2 in October 2017 and October 2018. By combining the historical strong earthquake background and modern seismic activity of the fault zone, the relation between the geochemical distribution characteristics of soil gas and the seismicity of the fault zone was studied herein. Furthermore, the strong seismic hazard potential of the fault zone was discussed. Results show that the concentration of soil gas Rn and CO2 considerably varies in the northern segment of the LPSFZ and is relatively stable in the southern segment. The spatial distribution of the concentration intensity and flux is strong in the north and weak in the south. However, the southern segment of the LPSFZ has a seismic gap that has not been ruptured by strong earthquakes with Ms ≥ 6.5 for the last 1400 years, whereas the seismic activity in the northern segment is relatively frequent, indicating that the fault zone locking degree of the southern segment is higher than that of the northern segment. This observation is completely consistent with the geochemical characteristic distribution of soil gas. Therefore, the southern segment of the LPSFZ should be considered a hazardous segment, where major or strong earthquakes can occur in the future.

SOIL GAS RADON MEASUREMENT AROUND FAULT LINES ON THE WESTERN SECTION OF THE NORTH ANATOLIAN FAULT ZONE IN TURKEY

2016 ◽  
pp. ncw009 ◽  
Author(s):  
Hakan Yakut ◽  
Emre Tabar ◽  
Eray Yıldırım ◽  
Zemine Zenginerler ◽  
Filiz Ertugral ◽  
...  
Keyword(s):  
Fault Zone ◽  
North Anatolian Fault ◽  
Soil Gas ◽  
North Anatolian Fault Zone ◽  
Radon Measurement ◽  
The North ◽  
Soil Gas Radon ◽  
Fault Lines

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.

Temporal Variation of Soil Gas Radon Associated with Seismic Activity: A Case Study in NW Greece

2019 ◽  
Vol 177 (2) ◽  
pp. 821-836 ◽  
Author(s):  
C. Papachristodoulou ◽  
K. Stamoulis ◽  
K. Ioannides
Keyword(s):  
Temporal Variation ◽  
Seismic Activity ◽  
Soil Gas ◽  
Soil Gas Radon

Correlations between soil gas and seismic activity in the Generalized Haiyuan Fault Zone, north-central China

2016 ◽  
Vol 85 (2) ◽  
pp. 763-776 ◽  
Author(s):  
Huiling Zhou ◽  
Hejun Su ◽  
Hui Zhang ◽  
Chenhua Li
Keyword(s):  
Fault Zone ◽  
Seismic Activity ◽  
Soil Gas ◽  
Central China ◽  
North Central

scholarly journals Comparative Analysis on Seismicity and Stress Triggering of Strong Earthquakes Sequence in Central Tibet

2021 ◽  
Author(s):  
Gang Yang ◽  
Dongning Lei ◽  
Jianchao Wu
Keyword(s):  
Fault Zone ◽  
Seismic Activity ◽  
Relaxation Effect ◽  
Earth Model ◽  
Coulomb Stress ◽  
Maximum Magnitude ◽  
Strong Earthquakes ◽  
Coulomb Stress Changes ◽  
Stress Changes ◽  
Central Tibet

Abstract The Central Tibet constitutes part of the central part of Qinghai-Tibetan Plateau, which is one of the highest seismic activity areas in China. This paper discussed the regularity of seismic activity in this area. Based on a stratified viscoelastic earth model, we calculated the Coulomb stress changes imparted from the 4 strong earthquakes (M≥6.3) the Bengco - southeastern piedmont of Nyainqentanglha mountain fault zone in this region. The result shows that the study area may enter a new active period from 2020. There was a trigger between strong earthquakes (M≥6.3) on the Bengco fault - southeastern piedmont of Nyainqentanglha mountain fault zone. The post-seismic viscous relaxation effect of a strong earthquake had a significant impact on subsequent earthquakes(M≥6.3). In future 100 years, the Coulomb stress loading is more than 1.0 MPa in northwest section of Bengco fault and central of Nimu segment of southeastern piedmont of Nyainqentanglha mountain fault, thence strong earthquakes may occur in this two fault segments. The maximum magnitude of the earthquake will be M6.7 in the future 100 years.

scholarly journals The Campotosto linkage fault zone between the 2009 and 2016 seismic sequences of central Italy: Implications for seismic hazard analysis

2020 ◽  
Author(s):  
Emanuele Tondi ◽  
Danica Jablonská ◽  
Tiziano Volatili ◽  
Maddalena Michele ◽  
Stefano Mazzoli ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Fault Zone ◽  
Central Italy ◽  
Seismic Events ◽  
Seismic Gap ◽  
Seismic Zone ◽  
Seismic Sequence ◽  
Geological Evidence ◽  
Seismic Sequences ◽  
Seismogenic Faults

In the last decade central Italy was struck by devastating seismic sequences resulting in hundreds of casualties (i.e., 2009-L′Aquila moment magnitude [Mw] = 6.3, and 2016-Amatrice-Visso-Norcia Mw max = 6.5). These seismic events were caused by two NW-SE−striking, SW-dipping, seismogenic normal faults that were modeled based on the available focal mechanisms and the seismic moment computed during the relative mainshocks. The seismogenic faults responsible for the 2009-L′Aquila Mw = 6.3 (Paganica Fault—PF) and 2016-Amatrice-Visso-Norcia Mw max = 6.5 (Monte Vettore Fault—MVF) are right-stepping with a negative overlap (i.e., underlap) located at the surface in the Campotosto area. This latter was affected by seismic swarms with magnitude ranging from 5.0 to 5.5 during the 2009 seismic sequence and then in 2017 (i.e., a few months later than the mainshocks related with the 2016 seismic sequence). In this paper, the seismogenic faults related to the main seismic events that occurred in the Campotosto Seismic Zone (CSZ) were modeled and interpreted as a linkage fault zone between the PF and MVF interacting seismogenic faults. Based on the underlap dimension, the seismogenic potential of the CSZ is in the order of Mw = 6.0, even in the case that all the faults belonging to the zone were activated simultaneously. This has important implications for seismic hazard assessment in an area dominated by the occurrence of a major NW-SE−striking extensional structure, i.e., the Monte Gorzano Fault (MGF). Mainly due to its geomorphologic expression, this fault has been considered as an active and silent structure (therefore representing a seismic gap) able to generate an earthquake of Mw max = 6.5−7.0. However, the geological evidence provided with this study suggests that the MGF is of early (i.e., pre- to syn-thrusting) origin. Therefore, the evaluation of the seismic hazard in the Campotosto area should not be based on the geometrical characteristics of the outcropping MGF. This also generates substantial issues with earthquake geological studies carried out prior to the recent seismic events in central Italy. More in general, the 4-D high-resolution image of a crustal volume hosting an active linkage zone between two large seismogenic structures provides new insights into the behavior of interacting faults in the incipient stages of connection.

Sign in / Sign up

Export Citation Format

Share Document