Joints significantly reduce rock cohesion compared to unfractured rock, but the question is what effect the possible anisotropy of the shear strength of different types of rupture has on possible subsequent failure. Both natural samples of granodiorite with natural joints and fault surfaces and gypsum models have been tested on the Matest A129 Rock shear box apparatus. The shear strength of preexisting ruptures was measured under a fixed normal stress component. The anisotropy of the shear strength of the joints and fault surfaces reached more than 60 % of maximum strength, which is a very important value for solving structural loads. The shear strength was analyzed with polar plots. The pattern of the real joints typically showed a teardrop shape with one peak of strength in a certain direction and a minimum in the opposite direction. On the contrary, striated fault surfaces are characterized by two axial directions of minimal shear strength, i.e., longitudinal and transverse, and by two axial oblique directions with maximal shear strength, so the strength distribution in the polar graph has a four-cornered shape. The study showed that the anisotropy of the shear strength of various types of ruptures is their important feature.
{"title":"Experimental study of rock ruptures shear strength anisotropy","authors":"Tomáš Proisl","doi":"10.13168/agg.2022.0001","DOIUrl":"https://doi.org/10.13168/agg.2022.0001","url":null,"abstract":"Joints significantly reduce rock cohesion compared to unfractured rock, but the question is what effect the possible anisotropy of the shear strength of different types of rupture has on possible subsequent failure. Both natural samples of granodiorite with natural joints and fault surfaces and gypsum models have been tested on the Matest A129 Rock shear box apparatus. The shear strength of preexisting ruptures was measured under a fixed normal stress component. The anisotropy of the shear strength of the joints and fault surfaces reached more than 60 % of maximum strength, which is a very important value for solving structural loads. The shear strength was analyzed with polar plots. The pattern of the real joints typically showed a teardrop shape with one peak of strength in a certain direction and a minimum in the opposite direction. On the contrary, striated fault surfaces are characterized by two axial directions of minimal shear strength, i.e., longitudinal and transverse, and by two axial oblique directions with maximal shear strength, so the strength distribution in the polar graph has a four-cornered shape. The study showed that the anisotropy of the shear strength of various types of ruptures is their important feature.","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43058686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The physical properties of tidal gravimetric instruments allow recording, not only tidal effects, but also waves generated by earthquakes. Three gravimetric stations with determined transfer functions and co-located seismic stations from the observatories in Western and Central Europe were selected for analysis. The observatories are equipped with almost all types of sensors available on the market, which allow for thorough analysis of earthquake recordings in the period range of 10–1000 s. In total, over 10,000 traces of worldwide earthquakes were investigated. The saturation levels of gravimeters as well as a correlation between the gravimetric and seismometric signals of an earthquake were carefully analysed. A simple processing scheme of gravimetric signal of earthquakes was adopted thanks to the probabilistic power spectral density analysis of continuous recordings. The detail analysis of transfer function of gravimeters allowed to define a period range when a sensitivity coefficient (calibration factor) and a time lag value only can be used to properly describe the properties of instruments. What’s more, it has been shown based on the calculated group-velocity dispersion curves of fundamental mode of Rayleigh waves, that the Earth’s mantle structure can be determined for greater depths from the recording of tidal gravimeters than from typical broad-band seismometers.
{"title":"Analysis of earthquakes recordings of tidal gravimeters in the period range of 10-1000 s","authors":"Kamila Karkowska","doi":"10.13168/agg.2021.0043","DOIUrl":"https://doi.org/10.13168/agg.2021.0043","url":null,"abstract":"The physical properties of tidal gravimetric instruments allow recording, not only tidal effects, but also waves generated by earthquakes. Three gravimetric stations with determined transfer functions and co-located seismic stations from the observatories in Western and Central Europe were selected for analysis. The observatories are equipped with almost all types of sensors available on the market, which allow for thorough analysis of earthquake recordings in the period range of 10–1000 s. In total, over 10,000 traces of worldwide earthquakes were investigated. The saturation levels of gravimeters as well as a correlation between the gravimetric and seismometric signals of an earthquake were carefully analysed. A simple processing scheme of gravimetric signal of earthquakes was adopted thanks to the probabilistic power spectral density analysis of continuous recordings. The detail analysis of transfer function of gravimeters allowed to define a period range when a sensitivity coefficient (calibration factor) and a time lag value only can be used to properly describe the properties of instruments. What’s more, it has been shown based on the calculated group-velocity dispersion curves of fundamental mode of Rayleigh waves, that the Earth’s mantle structure can be determined for greater depths from the recording of tidal gravimeters than from typical broad-band seismometers.","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46960518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Field observations in the northwest of Naein (Central Iran zone) indicate various types of alteration products have extended into pyroclastic and volcanic units with Oligomiocene age. It seems the Zefreh (with NWSE trend) and Kachumesqal (with E-W trend) faults are effective factors in the formation of Neysian and Barzavand copper deposits respectively. Alteration in Barzavand copper deposit (with stratabound form) includes pyritization, propylitization, zeolitization, saussuritization, uralitization and silicification, while in Neysian (with oval form) include phyllic, advanced argillic, argillic and propylitic. Geochemical studies in Barzavand show the positive correlation between (La/Lu)N, (La/Yb)N and (La/Sm)N and CaO (r= 0.70 to 0.96) related to propylitization of host rock basalt and increase in pH of fluids responsible for mineralization that play important role in differentiation of lanthanides in study area. The Barzavand copper deposit has submarine volcanism, diagenesis, burial metamorphism and weathering stages during its evolution. Remarkable geochemical features in Neysian include high (La/Lu)N, Ba and Sr values than La, Ce and Y. It seems that extensive alteration occurred along with hypogene and supergene processes in Neysian. According to alteration properties, mineralogy and the whole-rock geochemistry, the Barzavand and Neysian copper deposits are most similar to Mantotype and porphyry copper deposits respectively. ARTICLE INFO
{"title":"The Barzavand and Neysian Copper Deposits, NW Naein, Central Iran zone: Constraints on styles mineralization and geochemical signatures of hydrothermal alterations.","authors":"Shahram Mobaser","doi":"10.13168/agg.2021.0042","DOIUrl":"https://doi.org/10.13168/agg.2021.0042","url":null,"abstract":"Field observations in the northwest of Naein (Central Iran zone) indicate various types of alteration products have extended into pyroclastic and volcanic units with Oligomiocene age. It seems the Zefreh (with NWSE trend) and Kachumesqal (with E-W trend) faults are effective factors in the formation of Neysian and Barzavand copper deposits respectively. Alteration in Barzavand copper deposit (with stratabound form) includes pyritization, propylitization, zeolitization, saussuritization, uralitization and silicification, while in Neysian (with oval form) include phyllic, advanced argillic, argillic and propylitic. Geochemical studies in Barzavand show the positive correlation between (La/Lu)N, (La/Yb)N and (La/Sm)N and CaO (r= 0.70 to 0.96) related to propylitization of host rock basalt and increase in pH of fluids responsible for mineralization that play important role in differentiation of lanthanides in study area. The Barzavand copper deposit has submarine volcanism, diagenesis, burial metamorphism and weathering stages during its evolution. Remarkable geochemical features in Neysian include high (La/Lu)N, Ba and Sr values than La, Ce and Y. It seems that extensive alteration occurred along with hypogene and supergene processes in Neysian. According to alteration properties, mineralogy and the whole-rock geochemistry, the Barzavand and Neysian copper deposits are most similar to Mantotype and porphyry copper deposits respectively. ARTICLE INFO","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42776939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Long-term monitoring of the impact of the impact of mining operations on the ground surface at the regional scale based on the InSAR-SBAS technique, the Upper Silesian Coal Basin (Poland). Case study.","authors":"A. Kopec","doi":"10.13168/agg.2021.0044","DOIUrl":"https://doi.org/10.13168/agg.2021.0044","url":null,"abstract":"","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48118577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An integrated study of Landsat ETM and Cartosat DEM data in identification of banded iron formations (BIFs) associated with sulphide mineralization","authors":"Chandrashekharappa Agasnalli","doi":"10.13168/agg.2021.0041","DOIUrl":"https://doi.org/10.13168/agg.2021.0041","url":null,"abstract":"","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48436696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A historical and instrumental earthquake catalogue is prepared for the Northwest Himalayan Fold and Thrust Belt and Makran Subduction Zone Pakistan from 1960 to 2019 with homogenized moment magnitude. The local and some international published sources were utilized for the preparation of catalogue. This earthquake catalogue contained numbers of duplicate, repeated, dependent and independent events. Declustering process was opted to remove the dependent events such as foreshock and aftershock from catalogue to separate the mainshock only in term of distance and time space window. The declustering found 2714 clusters of earthquakes with total of 19512 (57.19 %) events out of 34112. Only cluster events which contained the main shock or independent events were drawn on seismicity map with color identification. Maximum likelihood method was used to compute the value of magnitude of completeness i.e., Mc = 3.8 with estimation of a and b-values. Years vise magnitude of completeness was also computed to check the time period variation. The completeness of magnitude for different intervals of time indicates the impartial approximation of previous recorded seismicity. Temporal and spatial maps were also drawn to investigate the slope “b” and rate of productivity “a” in the study region. It is noted that b-values varied from 0.2 to 2.0 due to stress and intensive tectonic setting whereas a value increases due to increase the seismicity rate with respect to region. Seismotectonic map was drawn to delineate the major faults, seismicity pattern and tectonic activities. This work further can be used for single value hazard assessment for any region and their response spectra to update buildings and bridges codes. ARTICLE INFO
{"title":"Statistical analysis of earthquake catalogue and magnitude of completeness for Northern and Southwestern Pakistan","authors":"S. Khurram","doi":"10.13168/agg.2021.0040","DOIUrl":"https://doi.org/10.13168/agg.2021.0040","url":null,"abstract":"A historical and instrumental earthquake catalogue is prepared for the Northwest Himalayan Fold and Thrust Belt and Makran Subduction Zone Pakistan from 1960 to 2019 with homogenized moment magnitude. The local and some international published sources were utilized for the preparation of catalogue. This earthquake catalogue contained numbers of duplicate, repeated, dependent and independent events. Declustering process was opted to remove the dependent events such as foreshock and aftershock from catalogue to separate the mainshock only in term of distance and time space window. The declustering found 2714 clusters of earthquakes with total of 19512 (57.19 %) events out of 34112. Only cluster events which contained the main shock or independent events were drawn on seismicity map with color identification. Maximum likelihood method was used to compute the value of magnitude of completeness i.e., Mc = 3.8 with estimation of a and b-values. Years vise magnitude of completeness was also computed to check the time period variation. The completeness of magnitude for different intervals of time indicates the impartial approximation of previous recorded seismicity. Temporal and spatial maps were also drawn to investigate the slope “b” and rate of productivity “a” in the study region. It is noted that b-values varied from 0.2 to 2.0 due to stress and intensive tectonic setting whereas a value increases due to increase the seismicity rate with respect to region. Seismotectonic map was drawn to delineate the major faults, seismicity pattern and tectonic activities. This work further can be used for single value hazard assessment for any region and their response spectra to update buildings and bridges codes. ARTICLE INFO","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47151936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Mariánské Lázně Fault (western Bohemia, CZE) is a morphologically, geologically and tectonically prominent structure with that is 150 km long with an NNW-SSE orientation. Its tectonic activity, especially in the NW part and in the neighbouring Cheb basin, is well known and has been proven by present-day earthquake swarms, mantle-derived CO2 emanations, geophysical and paleoseismological research. It seems that other parts of the MLF (especially segments of NNW-SSE and N-S orientation) might also have been active during the Pleistocene, possible even in the Holocene. This study provides a robust set of morphometric analyses – mountain-front sinuosity, basin asymmetry, longitudinal stream profiles, SL-index, which assesses the possibility of recent tectonic activity. The results suggest that the activity of the central and southern part of the MLF could have been very young. A reconstruction of the evolution of the stream network of the Mže River, as a result of different timing of the activity of particular segments of the MLF, is also put forward. The first ideas about the evolution of terrain morphology and the stream network are proposed by this study, however subsequent field research (geophysics, paleoseismology) could prove and date the tectonic activity. The delineation of segments with young activity may also have a great implication for seismic hazard assessment. ARTICLE INFO
{"title":"Geomorphological evidence of tectonic activity of the Marianske Lazne Fault (Czech Republic) and its influence to stream network evolution","authors":"J. Flašar","doi":"10.13168/agg.2021.0039","DOIUrl":"https://doi.org/10.13168/agg.2021.0039","url":null,"abstract":"The Mariánské Lázně Fault (western Bohemia, CZE) is a morphologically, geologically and tectonically prominent structure with that is 150 km long with an NNW-SSE orientation. Its tectonic activity, especially in the NW part and in the neighbouring Cheb basin, is well known and has been proven by present-day earthquake swarms, mantle-derived CO2 emanations, geophysical and paleoseismological research. It seems that other parts of the MLF (especially segments of NNW-SSE and N-S orientation) might also have been active during the Pleistocene, possible even in the Holocene. This study provides a robust set of morphometric analyses – mountain-front sinuosity, basin asymmetry, longitudinal stream profiles, SL-index, which assesses the possibility of recent tectonic activity. The results suggest that the activity of the central and southern part of the MLF could have been very young. A reconstruction of the evolution of the stream network of the Mže River, as a result of different timing of the activity of particular segments of the MLF, is also put forward. The first ideas about the evolution of terrain morphology and the stream network are proposed by this study, however subsequent field research (geophysics, paleoseismology) could prove and date the tectonic activity. The delineation of segments with young activity may also have a great implication for seismic hazard assessment. ARTICLE INFO","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43577361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fault identification for the catastrophic 1894 Atalanti earthquake using 3D finite-difference modelling and local geophysical data","authors":"E. Mouzakiotis","doi":"10.13168/agg.2021.0038","DOIUrl":"https://doi.org/10.13168/agg.2021.0038","url":null,"abstract":"","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42230050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study the compressive strength and durability of soft clay soil stabilized with halloysite nanotubes are investigated. Halloysite nanotubes are novel 1D natural nanomaterials which are widely used in reinforcing polymer, pollution remediation, and as nanoreactors for biocatalyst. The wide use of halloysite nanotubes is due to their high aspect ratio, appropriate mechanical strength, high thermal stability, nature-friendly and cost-effectiveness. However, the use of halloysite nanotubes as a stabilizing agent for improving the durability of soil is not clear. In this research, halloysite nanotubes was used in the amounts of 2 %, 5 % and 10 % by the weight of dried soil. Unconfined compressive strength, wet/dry cycles and freeze/thaw cycles tests were performed to evaluate the strength and durability of stabilized soft clay soil. Experimental results showed that halloysite nanotubes considerably improves the compressive strength and durability of soft clay soil. The optimum amount of halloysite nanotubes for soil stabilizing in terms of compressive strength and durability was 5 %. The compressive strength of soft clay increased as much as 129 % by applying 5 % halloysite nanotubes. Also, the specimen containing 5 % halloysite nanotubes showed the least strength loss after wet/dry and freeze/thaw cycles. The soil sample containing 5 % halloysite nanotubes lost 20 % of its initial compressive strength after 8 cycles of freezing and thawing, while the soil sample without any halloysite content lost 100 % of its compressive strength after the same number of freezing and thawing. Based on the obtained results, the use of halloysite nanotubes in order to enhance the strength and durability of soft clay is strongly recommended.
{"title":"Durability Assessment of soft clay soil stabilized with halloysite nanotubes","authors":"Masoud Tavakolipour","doi":"10.13168/agg.2021.0030","DOIUrl":"https://doi.org/10.13168/agg.2021.0030","url":null,"abstract":"In this study the compressive strength and durability of soft clay soil stabilized with halloysite nanotubes are investigated. Halloysite nanotubes are novel 1D natural nanomaterials which are widely used in reinforcing polymer, pollution remediation, and as nanoreactors for biocatalyst. The wide use of halloysite nanotubes is due to their high aspect ratio, appropriate mechanical strength, high thermal stability, nature-friendly and cost-effectiveness. However, the use of halloysite nanotubes as a stabilizing agent for improving the durability of soil is not clear. In this research, halloysite nanotubes was used in the amounts of 2 %, 5 % and 10 % by the weight of dried soil. Unconfined compressive strength, wet/dry cycles and freeze/thaw cycles tests were performed to evaluate the strength and durability of stabilized soft clay soil. Experimental results showed that halloysite nanotubes considerably improves the compressive strength and durability of soft clay soil. The optimum amount of halloysite nanotubes for soil stabilizing in terms of compressive strength and durability was 5 %. The compressive strength of soft clay increased as much as 129 % by applying 5 % halloysite nanotubes. Also, the specimen containing 5 % halloysite nanotubes showed the least strength loss after wet/dry and freeze/thaw cycles. The soil sample containing 5 % halloysite nanotubes lost 20 % of its initial compressive strength after 8 cycles of freezing and thawing, while the soil sample without any halloysite content lost 100 % of its compressive strength after the same number of freezing and thawing. Based on the obtained results, the use of halloysite nanotubes in order to enhance the strength and durability of soft clay is strongly recommended.","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47107108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Artefacts in gravity field modelling","authors":"J. Klokočník","doi":"10.13168/agg.2021.0037","DOIUrl":"https://doi.org/10.13168/agg.2021.0037","url":null,"abstract":"","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42050430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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