Wavelet analysis of the temporal-spatial distribution in the Eurasia seismic belt

2017 ◽  
Vol 15 (03) ◽  
pp. 1750018 ◽  
Author(s):  
Wenfeng Zheng ◽  
Xiaolu Li ◽  
Lirong Yin ◽  
Zhengtong Yin ◽  
Bo Yang ◽  
...  
Keyword(s):  
Fault Zone ◽  
Compact Support ◽  
Large Scale ◽  
Temporal Distribution ◽  
Seismic Energy ◽  
Research Area ◽  
Earthquake Activity ◽  
Seismic Zone ◽  
Seismic Belt ◽  
Earthquake Fault

Due to the growing frequency of earthquakes, safeties of human lives and properties are facing serious threats. However, the research in the field of spatial-temporal distribution of earthquake is quite a few. In this paper, we use wavelet model to analyze the spatial-temporal distribution of earthquakes. Because the spatial-temporal distribution of earthquake activity is closely related to the distribution of the earthquake fault zone, we analyze large-scale earthquake clusters by selecting the Eurasia seismic belt and the surrounding region as the research area. From the perspective of the time domain, the results show that the seismic energy of the earthquake fault zone presences compact support or similar compact support distribution, suggesting that the seismic zone exists a relatively quiet period and active stage. This indicate that the seismic zone is periodical. The period of strong earthquakes above normal and less than normal is different by time changes. The cycles of earthquakes are different due to different regions and different geological and geographical environment.

scholarly journals Large-scale electrical resistivity tomography in the Cheb Basin (Eger Rift) at an International Continental Drilling Program (ICDP) monitoring site to image fluid-related structures

Solid Earth ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 1951-1969 ◽  
Author(s):  
Tobias Nickschick ◽  
Christina Flechsig ◽  
Jan Mrlina ◽  
Frank Oppermann ◽  
Felix Löbig ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Fault Zone ◽  
Large Scale ◽  
Monitoring Site ◽  
Earthquake Activity ◽  
Resistivity Tomography ◽  
Scientific Drilling ◽  
Eger Rift ◽  
Geophysical Surveys ◽  
Cheb Basin

Abstract. The Cheb Basin, a region of ongoing swarm earthquake activity in the western Czech Republic, is characterized by intense carbon dioxide degassing along two known fault zones – the N–S-striking Počatky–Plesná fault zone (PPZ) and the NW–SE-striking Mariánské Lázně fault zone (MLF). The fluid pathways for the ascending CO2 of mantle origin are one of the subjects of the International Continental Scientific Drilling Program (ICDP) project “Drilling the Eger Rift” in which several geophysical surveys are currently being carried out in this area to image the topmost hundreds of meters to assess the structural situation, as existing boreholes are not sufficiently deep to characterize it. As electrical resistivity is a sensitive parameter to the presence of conductive rock fractions as liquid fluids, clay minerals, and also metallic components, a large-scale dipole–dipole experiment using a special type of electric resistivity tomography (ERT) was carried out in June 2017 in order to image fluid-relevant structures. We used permanently placed data loggers for voltage measurements in conjunction with moving high-power current sources to generate sufficiently strong signals that could be detected all along the 6.5 km long profile with 100 and 150 m dipole spacings. After extensive processing of time series for voltage and current using a selective stacking approach, the pseudo-section is inverted, which results in a resistivity model that allows for reliable interpretations depths of up than 1000 m. The subsurface resistivity image reveals the deposition and transition of the overlying Neogene Vildštejn and Cypris formations, but it also shows a very conductive basement of phyllites and granites that can be attributed to high salinity or rock alteration by these fluids in the tectonically stressed basement. Distinct, narrow pathways for CO2 ascent are not observed with this kind of setup, which hints at wide degassing structures over several kilometers within the crust instead. We also observed gravity and GPS data along this profile in order to constrain ERT results. A gravity anomaly of ca. −9 mGal marks the deepest part of the Cheb Basin where the ERT profile indicates a large accumulation of conductive rocks, indicating a very deep weathering or alteration of the phyllitic basement due to the ascent of magmatic fluids such as CO2. We propose a conceptual model in which certain lithologic layers act as caps for the ascending fluids based on stratigraphic records and our results from this experiment, providing a basis for future drillings in the area aimed at studying and monitoring fluids.

scholarly journals Large-scale electrical resistivity tomography in the Cheb Basin (Eger Rift) at an ICDP monitoring drill site to image fluid-related structures

2019 ◽  
Author(s):  
Tobias Nickschick ◽  
Christina Flechsig ◽  
Jan Mrlina ◽  
Frank Oppermann ◽  
Felix Löbig ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Fault Zone ◽  
Large Scale ◽  
Earthquake Activity ◽  
Resistivity Tomography ◽  
Near Surface ◽  
Scientific Drilling ◽  
Eger Rift ◽  
Geophysical Surveys ◽  
Cheb Basin

Abstract. The Cheb Basin, a region of ongoing swarm earthquake activity in the western Czech Republic, is characterized by intense carbon dioxide degassing along two known fault zones – the N-S-striking Počatky-Plesná fault zone (PPZ) and the NW-SE-striking Mariánské Lázně fault zone (MLF). The fluid pathways for the ascending CO2 of mantle origin are subject of an International Continental Scientific Drilling Program (ICDP) project in which several geophysical surveys are currently carried out to image the near-surface geologic situation, as existing boreholes are not sufficiently deep to characterize the structures. As electrical resistivity is a sensitive parameter to the presence of low-resistivity rock fractions as liquid fluids, clay minerals and also metallic components, a large-scale dipole-dipole experiment using a special type of electric resistivity tomography (ERT) was carried out in June 2017 in order to image fluid-relevant structures. We used static remote-controlled data loggers in conjunction with high-power current sources for generating sufficiently strong signals that could be detected all along the 6.5 km long profile with 100 m and 150 m dipole spacings. Extensive processing of time series and apparent resistivity data lead to a full pseudosection and allowing interpretation depths of more than 1000 m. The subsurface resistivity image reveals the deposition and transition of the overlying Neogene Vildštejn and Cypris formations, but also shows a very conductive basement of phyllites and granites that can be attributed to high salinization or rock alteration by these fluids in the tectonically stressed basement. Distinct, narrow pathways for CO2 ascent are not observed with this kind of setup which hints at wide degassing structures over several kilometers within the crust instead. We also observed gravity/GPS data along this profile in order to constrain ERT results. Gravity clearly shows the deepest part of the Cheb Basin along the profile, its limitation by MLF at NE end, but also shallower basement with an assumed basic intrusion in SW part of profile. We propose a conceptual model in which certain lithological layers act as caps for the ascending fluids, based on stratigraphic records and our results from this experiment, providing a basis for future drills in the area aimed at studying and monitoring fluids.

Advances in Water Treatment Application of Sepiolite Mineral Materials

2013 ◽  
Vol 710 ◽  
pp. 217-220 ◽  
Author(s):  
Fei Wang ◽  
Lei Feng ◽  
Meng Ran Tang ◽  
Ji Yuan Li ◽  
Qing Guo Tang
Keyword(s):  
Water Treatment ◽  
Size Effect ◽  
Large Scale ◽  
Surface Effect ◽  
Development Trend ◽  
High Energy ◽  
Research Area ◽  
Group Mineral ◽  
Active Research ◽  
Treatment Application

Synthetic nanomaterials have the disadvantages of large-scale investment, high energy consumption, complex production process and heavy environmental load. Mineral nanomaterials such as sepiolite group mineral nanomaterials are characterized by small size effect, quantum size effect and surface effect. Water treatment application of sepiolite group mineral nanomaterials has become an active research area and showed good development and application prospects. Based on the above reasons, this paper systematically summarizes the water treatment application of sepiolite group mineral nanomaterials, and development trend related to water treatment application of sepiolite group mineral nanomaterials were also proposed.

scholarly journals Active Fault Systems in the Inner Northwest Apennines, Italy: A Reappraisal One Century after the 1920 Mw ~6.5 Fivizzano Earthquake

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 139
Author(s):  
Giancarlo Molli ◽  
Isabelle Manighetti ◽  
Rick Bennett ◽  
Jacques Malavieille ◽  
Enrico Serpelloni ◽  
...  
Keyword(s):  
Large Scale ◽  
Active Fault ◽  
Active Faults ◽  
Dense Network ◽  
Earthquake Fault ◽  
Slip Rates ◽  
Fault Systems ◽  
Seismological Data ◽  
Seismogenic Faults

Based on the review of the available stratigraphic, tectonic, morphological, geodetic, and seismological data, along with new structural observations, we present a reappraisal of the potential seismogenic faults and fault systems in the inner northwest Apennines, Italy, which was the site, one century ago, of the devastating Mw ~6.5, 1920 Fivizzano earthquake. Our updated fault catalog provides the fault locations, as well as the description of their architecture, large-scale segmentation, cumulative displacements, evidence for recent to present activity, and long-term slip rates. Our work documents that a dense network of active faults, and thus potential earthquake fault sources, exists in the region. We discuss the seismogenic potential of these faults, and propose a general tectonic scenario that might account for their development.

The reproducing earthquakes of the Galapagos Islands

1980 ◽  
Vol 70 (5) ◽  
pp. 1759-1770
Author(s):  
Kris Kaufman ◽  
L. J. Burdick
Keyword(s):  
Large Scale ◽  
Fault Plane ◽  
Seismic Energy ◽  
Galapagos Islands ◽  
The Body ◽  
Galápagos Islands ◽  
Plane Solution ◽  
Extensional Faulting ◽  
Strain Release ◽  
Wave Trains

abstract The largest swarm of earthquakes of the last few decades accompanied the collapse of the Fernandina caldera in the Galapagos Islands in June of 1968. Many of the events were relatively large. (The largest 21 had moments ranging from 6 ×1024 to 12 ×1024 dyne-cm.) They produced teleseismic WWSSN records that were spectacularly consistent from event to event. The entire wave trains of the signals were nearly identical on any given component at any given station. This indicates that the mode of strain release in the region was unusually stable and coherent. The body waveforms of the events have been modeled with synthetic seismograms. The best fault plane solution was found to be: strike = 335°, dip = 47°, and rake = 247°. The depths of all the larger shocks were close to 14 km. Previous work had suggested that the seismic energy was radiated by the collapsing caldera block at a depth of about 1 km. The new results indicate that large scale extensional faulting at depth was an important part of the multifaceted event during which the caldera collapsed.

scholarly journals Carbonaceous Materials in the Fault Zone of the Longmenshan Fault Belt: 1. Signatures within the Deep Wenchuan Earthquake Fault Zone and Their Implications

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 385 ◽  
Author(s):  
Li-Wei Kuo ◽  
Jyh-Rou Huang ◽  
Jiann-Neng Fang ◽  
Jialiang Si ◽  
Haibing Li ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Fault Zone ◽  
Active Fault ◽  
Carbonaceous Materials ◽  
Coseismic Slip ◽  
Earthquake Fault ◽  
Active Fault Zone ◽  
2008 Wenchuan Earthquake ◽  
Seismic Slip ◽  
Longmenshan Fault

Graphitization of carbonaceous materials (CM) has been experimentally demonstrated as potential evidence of seismic slip within a fault gouge. The southern segment of the Longmenshan fault, a CM-rich-gouge fault, accommodated coseismic slip during the 2008 Mw 7.9 Wenchuan earthquake and potentially preserves a record of processes that occurred on the fault during the slip event. Here, we present a multi-technique characterization of CM within the active fault zone of the Longmenshan fault from the Wenchuan earthquake Fault Scientific Drilling-1. By contrast with field observations, graphite is pervasively and only distributed in the gouge zone, while heterogeneously crystallized CM are present in the surrounding breccia. The composite dataset that is presented, which includes the localized graphite layer along the 2008 Wenchuan earthquake principal slip zone, demonstrates that graphite is widely distributed within the active fault zone. The widespread occurrence of graphite, a seismic slip indicator, reveals that surface rupturing events commonly occur along the Longmenshan fault and are characteristic of this tectonically active region.

scholarly journals P-wave crustal tomography of Greece with use of an accurate two-point ray tracer

1997 ◽  
Vol 40 (1) ◽  
Author(s):  
G. Drakatos ◽  
G. Karantonis ◽  
G. N. Stavrakakis
Keyword(s):  
Large Scale ◽  
Velocity Structure ◽  
Three Dimensional ◽  
Seismic Energy ◽  
Aegean Sea ◽  
P Wave ◽  
Low Velocity ◽  
Aegean Area ◽  
Arrival Times ◽  
Horizontal Variations

The three-dimensional velocity structure of the crust in the Aegean sea and the surrounding regions (34.0º-42.OºN, 19.0ºE-29.0ºE) is investigated by inversion of about 10000 residuals of arrival times of P-wave from local events. The resulting velocity structure shows strong horizontal variations due to the complicated crustal structure and the variations of crustal thickness. The northern part of the region generally shows high velocities. In the inner part of the volcanic arc (Southern Aegean area), relatively low velocities are observed, suggesting a large-scale absorption of seismic energy as confirmed by the low seismicity of the region. A low velocity zone was observed along the subduction zone of the region, up to a depth of 4 km. The existence of such a zone could be due to granitic or other intrusions in the crust during the uplift of the region during Alpidic orogenesis.

scholarly journals Large Evaporite Provinces: Geothermal rather than Solar Origin?

2020 ◽  
Author(s):  
Zhanjie Qin ◽  
Chunan Tang ◽  
Xiying Zhang ◽  
Tiantian Chen ◽  
Xiangjun Liu ◽  
...  
Keyword(s):  
Large Scale ◽  
Climatic Factors ◽  
Temporal Distribution ◽  
Tectonic Activity ◽  
Driving Mechanism ◽  
Solar Origin ◽  
Tectonically Active ◽  
Spatio Temporal ◽  
Thermal Influence ◽  
The Masses

Abstract Large evaporite provinces (LEPs) represent prodigious volumes of evaporites widely developed from the Sinian to Neogene. The reasons why they often quickly develop on a large scale with large areas and thicknesses remain enigmatic. Possible causes range from warming from above to heating from below. The fact that the salt deposits in most salt-bearing basins occur mainly in the Sinian-Cambrian, Permian-Triassic, Jurassic-Cretaceous, and Miocene intervals favours a dominantly tectonic origin rather than a solar driving mechanism. Here, we analysed the spatio-temporal distribution of evaporites based on 138 evaporitic basins and found that throughout the Phanerozoiceon, LEPs occurred across the Earth’s surface in most salt-bearing basins, especially in areas with an evolutionary history of strong tectonic activity. The masses of evaporites, rates of evaporite formation, tectonic movements, and large igneous provinces (LIPs) synergistically developed in the Sinian-Cambrian, Permian, Jurassic-Cretaceous, and Miocene intervals, which are considered to be four of the warmest times since the Sinian. We realize that salt accumulation can proceed without solar energy and can generally be linked to geothermal changes in tectonically active zones. When climatic factors are involved, they may be manifestations of the thermal influence of the crust on the surface.

scholarly journals Methodical approach to determining permissible time limits of intermittent carbon monoxide exposure in rescuers

2021 ◽  
pp. 82-88
Author(s):  
D. V. Myasnikov ◽  
P. V. Avitisov ◽  
A. V. Zolotukhin ◽  
M. F. Barinov
Keyword(s):  
Carbon Monoxide ◽  
Large Scale ◽  
Operation Time ◽  
Theoretical Data ◽  
Combustion Products ◽  
Research Area ◽  
Time Limits ◽  
Emergency Rescue ◽  
Functional Relationships ◽  
Methodical Approach

Relevance. Current operation time limits under hazardous chemical conditions (“emergency regulations”) have been developed mainly for a limited number of emergency situations occurring in spacecraft, submarines or other specific objects. At the same time, many emergencies accompanied by large-scale releases of toxic combustion products from various materials and compounds into the environment are not limited to these facilities. Therefore, risks associated with toxic effects of chemicals should be predicted, since permissible time limits with adequate performance of personnel under certain chemical exposures are used for individual protection (time-based protection).Intention: On the basis of physiological aspects, the peculiarities of the work performed by rescuers and the requirements for organizing and conducting emergency rescue operations, to propose a methodical approach to determining the permissible time for rescuers in conditions of intermittent carbon monoxide release.Methodology. The scientific works and results of experiments in the research area were analyzed. Systematization and generalization of empirical and theoretical data, traditional analysis of documents and publications were used with the least squares approximation.Results and Discussion. Specific effects of various carbon monoxide concentrations are shown for different exposure times. Critical concentrations and exposure times are revealed, functional relationships between permissible time of operation and carbon monoxide concentrations are determined. Carboxyhemoglobin formation and effects were taken into account.Conclusion. The data given in the article are an important basis for organizing and conducting emergency rescue operations at increased concentrations of carbon monoxide.

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