M. Chilinski, K. Markowicz, Olga Zawadzka, I. Stachlewska, Wojciech Kumala, T. Petelski, P. Makuch, D. Westphal, Bogdan Zagajewski
This paper is focused on Saharan dust transport to Central Europe/Poland; we compare properties of atmospheric Saharan dust using data from NAAPS, MACC, AERONET as well as observations obtained during HyMountEcos campaign in June 2012. Ten years of dust climatology shows that long-range transport of Saharan dust to Central Europe is mostly during spring and summer. HYSPLIT back-trajectories indicate airmass transport mainly in November, but it does not agree with modeled maxima of dust optical depth. NAAPS model shows maximum of dust optical depth (~0.04–0.05, 550 nm) in April–May, but the MACC modeled peak is broader (~0.04). During occurrence of mineral dust over Central-Europe for 14% (NAAPS) / 12% (MACC) of days dust optical depths are above 0.05 and during 4% (NAAPS) / 2.5% (MACC) of days dust optical depths exceed 0.1. The HyMountEcos campaign took place in June–July 2012 in the mountainous region of Karkonosze. The analysis includes remote sensing data from lidars, sunphotometers, and numerical simulations from NAAPS, MACC, DREAM8b models. Comparison of simulations with observations demonstrates the ability of models to reasonably reproduce aerosol vertical distributions and their temporal variability. However, significant differences between simulated and measured AODs were found. The best agreement was achieved for MACC model.
{"title":"Modelling and Observation of Mineral Dust Optical Properties over Central Europe","authors":"M. Chilinski, K. Markowicz, Olga Zawadzka, I. Stachlewska, Wojciech Kumala, T. Petelski, P. Makuch, D. Westphal, Bogdan Zagajewski","doi":"10.1515/acgeo-2016-0069","DOIUrl":"https://doi.org/10.1515/acgeo-2016-0069","url":null,"abstract":"This paper is focused on Saharan dust transport to Central Europe/Poland; we compare properties of atmospheric Saharan dust using data from NAAPS, MACC, AERONET as well as observations obtained during HyMountEcos campaign in June 2012. Ten years of dust climatology shows that long-range transport of Saharan dust to Central Europe is mostly during spring and summer. HYSPLIT back-trajectories indicate airmass transport mainly in November, but it does not agree with modeled maxima of dust optical depth. NAAPS model shows maximum of dust optical depth (~0.04–0.05, 550 nm) in April–May, but the MACC modeled peak is broader (~0.04). During occurrence of mineral dust over Central-Europe for 14% (NAAPS) / 12% (MACC) of days dust optical depths are above 0.05 and during 4% (NAAPS) / 2.5% (MACC) of days dust optical depths exceed 0.1. The HyMountEcos campaign took place in June–July 2012 in the mountainous region of Karkonosze. The analysis includes remote sensing data from lidars, sunphotometers, and numerical simulations from NAAPS, MACC, DREAM8b models. Comparison of simulations with observations demonstrates the ability of models to reasonably reproduce aerosol vertical distributions and their temporal variability. However, significant differences between simulated and measured AODs were found. The best agreement was achieved for MACC model.","PeriodicalId":50898,"journal":{"name":"Acta Geophysica","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2016-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/acgeo-2016-0069","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67090953","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}
M. Kubicki, A. Odzimek, M. Neska, J. Berliński, S. Michnowski
Atmospheric electricity measurements are performed all over the globe for getting a better understanding of the processes and phenomena operating in the Earth’s electric atmosphere, ionosphere and magnetosphere. Over recent years, we have established coordinated observations of atmospheric electricity, mainly of the vertical component of the Earth’s atmospheric electric field, from Polish observation stations: Stanisław Kalinowski Geophysical Observatory in Świder, Poland, Stanisław Siedlecki Polar Station in Hornsund, Svalbard, Norway, and, for the first time, the Henryk Arctowski Antarctic Station in King George Island. The organisation of this network is presented here as well as a preliminary summary of geophysical conditions at Arctowski, important from the point of view of atmospheric electricity observations. In particular, we refer to the geomagnetic observations made at Arctowski station in 1978–1995. We also present the average fair-weather diurnal variation of the atmospheric electric field based on observations made so far between 2013 and 2015.
{"title":"First Measurements of the Earth’s Electric Field at the Arctowski Antarctic Station, King George Island, by the New Polish Atmospheric Electricity Observation Network","authors":"M. Kubicki, A. Odzimek, M. Neska, J. Berliński, S. Michnowski","doi":"10.1515/acgeo-2016-0096","DOIUrl":"https://doi.org/10.1515/acgeo-2016-0096","url":null,"abstract":"Atmospheric electricity measurements are performed all over the globe for getting a better understanding of the processes and phenomena operating in the Earth’s electric atmosphere, ionosphere and magnetosphere. Over recent years, we have established coordinated observations of atmospheric electricity, mainly of the vertical component of the Earth’s atmospheric electric field, from Polish observation stations: Stanisław Kalinowski Geophysical Observatory in Świder, Poland, Stanisław Siedlecki Polar Station in Hornsund, Svalbard, Norway, and, for the first time, the Henryk Arctowski Antarctic Station in King George Island. The organisation of this network is presented here as well as a preliminary summary of geophysical conditions at Arctowski, important from the point of view of atmospheric electricity observations. In particular, we refer to the geomagnetic observations made at Arctowski station in 1978–1995. We also present the average fair-weather diurnal variation of the atmospheric electric field based on observations made so far between 2013 and 2015.","PeriodicalId":50898,"journal":{"name":"Acta Geophysica","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2016-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/acgeo-2016-0096","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67091717","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}
S. Syuhada, N. Hananto, C. I. Abdullah, N. Puspito, T. Anggono, T. Yudistira
We analyzed receiver function of teleseismic events recorded at twelve Indonesian-GEOFON (IA-GE) broadband stations using nonlinear Neighbourhood Algorithm (NA) inversion and H-k stacking methods to estimate crustal thickness, Vp/Vs ratios and S-wave velocity structure along Sunda-Banda arc transition zone. We observed crustal thickness of 34–37 km in Timor Island, which is consistent with the previous works. The thick crust (> 30 km) is also found beneath Sumba and Flores Islands, which might be related to the arc-continent collision causing the thickened crust. In Timor and Sumba Islands, we observed high Vp/Vs ratio (> 1.84) with low velocity zone that might be associated with the presence of mafic and ultramafic materials and fluid filled fracture zone. The high Vp/Vs ratio observed at Sumbawa and Flores volcanic Islands might be an indication of partial melt related to the upwelling of hot asthenosphere material through the subducted slab.
{"title":"Crustal Structure Along Sunda-Banda Arc Transition Zone from Teleseismic Receiver Functions","authors":"S. Syuhada, N. Hananto, C. I. Abdullah, N. Puspito, T. Anggono, T. Yudistira","doi":"10.1515/acgeo-2015-0098","DOIUrl":"https://doi.org/10.1515/acgeo-2015-0098","url":null,"abstract":"We analyzed receiver function of teleseismic events recorded at twelve Indonesian-GEOFON (IA-GE) broadband stations using nonlinear Neighbourhood Algorithm (NA) inversion and H-k stacking methods to estimate crustal thickness, Vp/Vs ratios and S-wave velocity structure along Sunda-Banda arc transition zone. We observed crustal thickness of 34–37 km in Timor Island, which is consistent with the previous works. The thick crust (> 30 km) is also found beneath Sumba and Flores Islands, which might be related to the arc-continent collision causing the thickened crust. In Timor and Sumba Islands, we observed high Vp/Vs ratio (> 1.84) with low velocity zone that might be associated with the presence of mafic and ultramafic materials and fluid filled fracture zone. The high Vp/Vs ratio observed at Sumbawa and Flores volcanic Islands might be an indication of partial melt related to the upwelling of hot asthenosphere material through the subducted slab.","PeriodicalId":50898,"journal":{"name":"Acta Geophysica","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2016-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/acgeo-2015-0098","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67088005","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 paper, an experimental investigation of sandstone samples from the Three Gorges during shear failure was conducted using acoustic emission (AE) and direct shear tests. The AE count rate, cumulative AE count, AE energy, and amplitude of the sandstone samples were determined. Then, the relationships among the AE signals and shearing behaviors of the samples were analyzed in order to detect micro-crack initiation and propagation and reflect shear failure. The results indicated that both the shear strength and displacement exhibited a logarithmic relationship with the displacement rate at peak levels of stress. In addition, the various characteristics of the AE signals were apparent in various situations. The AE signals corresponded with the shear stress under different displacement rates. As the displacement rate increased, the amount of accumulative damage to each specimen decreased, while the AE energy peaked earlier and more significantly. The cumulative AE count primarily increased during the post-peak period. Furthermore, the AE count rate and amplitude exhibited two peaks during the peak shear stress period due to crack coalescence and rock bridge breakage. These isolated cracks later formed larger fractures and eventually caused ruptures.
{"title":"Acoustic Emission Parameters of Three Gorges Sandstone during Shear Failure","authors":"Jiang Xu, Yixin Liu, S. Peng","doi":"10.1515/acgeo-2016-0094","DOIUrl":"https://doi.org/10.1515/acgeo-2016-0094","url":null,"abstract":"In this paper, an experimental investigation of sandstone samples from the Three Gorges during shear failure was conducted using acoustic emission (AE) and direct shear tests. The AE count rate, cumulative AE count, AE energy, and amplitude of the sandstone samples were determined. Then, the relationships among the AE signals and shearing behaviors of the samples were analyzed in order to detect micro-crack initiation and propagation and reflect shear failure. The results indicated that both the shear strength and displacement exhibited a logarithmic relationship with the displacement rate at peak levels of stress. In addition, the various characteristics of the AE signals were apparent in various situations. The AE signals corresponded with the shear stress under different displacement rates. As the displacement rate increased, the amount of accumulative damage to each specimen decreased, while the AE energy peaked earlier and more significantly. The cumulative AE count primarily increased during the post-peak period. Furthermore, the AE count rate and amplitude exhibited two peaks during the peak shear stress period due to crack coalescence and rock bridge breakage. These isolated cracks later formed larger fractures and eventually caused ruptures.","PeriodicalId":50898,"journal":{"name":"Acta Geophysica","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2016-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/acgeo-2016-0094","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67091692","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 spatial location of sources of seismic waves is one of the first tasks when transient waves from natural (uncontrolled) sources are analysed in many branches of physics, including seismology, oceanology, to name a few. It is well recognised that there is no single universal location algorithm which performs equally well in all situations. Source activity and its spatial variability in time, the geometry of recording network, the complexity and heterogeneity of wave velocity distribution are all factors influencing the performance of location algorithms. In this paper we propose a new location algorithm which exploits the reciprocity and time-inverse invariance property of the wave equation. Basing on these symmetries and using a modern finite-difference-type eikonal solver, we have developed a new very fast algorithm performing the full probabilistic (Bayesian) source location. We illustrate an efficiency of the algorithm performing an advanced error analysis for 1647 seismic events from the Rudna copper mine operating in southwestern Poland.
{"title":"The New Algorithm for Fast Probabilistic Hypocenter Locations","authors":"W. Debski, P. Klejment","doi":"10.1515/acgeo-2016-0111","DOIUrl":"https://doi.org/10.1515/acgeo-2016-0111","url":null,"abstract":"The spatial location of sources of seismic waves is one of the first tasks when transient waves from natural (uncontrolled) sources are analysed in many branches of physics, including seismology, oceanology, to name a few. It is well recognised that there is no single universal location algorithm which performs equally well in all situations. Source activity and its spatial variability in time, the geometry of recording network, the complexity and heterogeneity of wave velocity distribution are all factors influencing the performance of location algorithms. In this paper we propose a new location algorithm which exploits the reciprocity and time-inverse invariance property of the wave equation. Basing on these symmetries and using a modern finite-difference-type eikonal solver, we have developed a new very fast algorithm performing the full probabilistic (Bayesian) source location. We illustrate an efficiency of the algorithm performing an advanced error analysis for 1647 seismic events from the Rudna copper mine operating in southwestern Poland.","PeriodicalId":50898,"journal":{"name":"Acta Geophysica","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2016-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/acgeo-2016-0111","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67092959","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}
S. Tavakoli, Mahdieh Dehghannejad, María Ángeles García Juanatey, Tobias E. Bauer, P. Weihed, S. Elming
Multi-scale geophysical studies were conducted in the central Skellefte district (CSD) in order to delineate the geometry of the upper crust (down to maximum ∼ 4.5 km depth) for prospecting volcanic massive sulphide (VMS) mineralization. These geophysical investigations include potential field, resistivity/induced polarization (IP), reflection seismic and magnetotelluric (MT) data which were collected between 2009 and 2010. The interpretations were divided in two scales: (i) shallow (∼ 1.5 km) and (ii) deep (∼4.5 km). Physical properties of the rocks, including density, magnetic susceptibility, resistivity and chargeability, were also used to improve interpretations. The study result delineates the geometry of the upper crust in the CSD and new models were suggested based on new and joint geophysical interpretation which can benefit VMS prospecting in the area. The result also indicates that a strongly conductive zone detected by resistivity/IP data may have been missed using other geophysical data.
{"title":"Potential Field, Geoelectrical and Reflection Seismic Investigations for Massive Sulphide Exploration in the Skellefte Mining District, Northern Sweden","authors":"S. Tavakoli, Mahdieh Dehghannejad, María Ángeles García Juanatey, Tobias E. Bauer, P. Weihed, S. Elming","doi":"10.1515/acgeo-2016-0088","DOIUrl":"https://doi.org/10.1515/acgeo-2016-0088","url":null,"abstract":"Multi-scale geophysical studies were conducted in the central Skellefte district (CSD) in order to delineate the geometry of the upper crust (down to maximum ∼ 4.5 km depth) for prospecting volcanic massive sulphide (VMS) mineralization. These geophysical investigations include potential field, resistivity/induced polarization (IP), reflection seismic and magnetotelluric (MT) data which were collected between 2009 and 2010. The interpretations were divided in two scales: (i) shallow (∼ 1.5 km) and (ii) deep (∼4.5 km). Physical properties of the rocks, including density, magnetic susceptibility, resistivity and chargeability, were also used to improve interpretations. The study result delineates the geometry of the upper crust in the CSD and new models were suggested based on new and joint geophysical interpretation which can benefit VMS prospecting in the area. The result also indicates that a strongly conductive zone detected by resistivity/IP data may have been missed using other geophysical data.","PeriodicalId":50898,"journal":{"name":"Acta Geophysica","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2016-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/acgeo-2016-0088","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67091568","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}
Current human activity produces strong electromagnetic pollution. The power spectrum in the extremely low frequency (ELF, 3–3000 Hz) range is mainly polluted by anthropogenic narrow spectral lines at 16.66, 50, and 60 Hz and their harmonics. Meanwhile, signatures connected with natural phenomena appearing in the Earth’s atmosphere, ionosphere and magnetosphere are also observed in the same frequency range.This paper presents the amplitude behaviour of the anthropogenic lines in the years 2005–2014 based on the 10 years of activity of the Hylaty station situated in southeast Poland. The analysis includes, i.a., an assessment of the correctness of the choice of the Bieszczady mountains as a location for the installation of an ELF station for long-term geophysical and climatological studies.
{"title":"Imprints of Natural Phenomena and Human Activity Observed During 10 Years of ELF Magnetic Measurements at the Hylaty Geophysical Station in Poland","authors":"Z. Nieckarz","doi":"10.1515/acgeo-2016-0101","DOIUrl":"https://doi.org/10.1515/acgeo-2016-0101","url":null,"abstract":"Current human activity produces strong electromagnetic pollution. The power spectrum in the extremely low frequency (ELF, 3–3000 Hz) range is mainly polluted by anthropogenic narrow spectral lines at 16.66, 50, and 60 Hz and their harmonics. Meanwhile, signatures connected with natural phenomena appearing in the Earth’s atmosphere, ionosphere and magnetosphere are also observed in the same frequency range.This paper presents the amplitude behaviour of the anthropogenic lines in the years 2005–2014 based on the 10 years of activity of the Hylaty station situated in southeast Poland. The analysis includes, i.a., an assessment of the correctness of the choice of the Bieszczady mountains as a location for the installation of an ELF station for long-term geophysical and climatological studies.","PeriodicalId":50898,"journal":{"name":"Acta Geophysica","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2016-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/acgeo-2016-0101","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67092381","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 interpretation of seismic refraction and wide angle reflection data usually involves the creation of a velocity model based on an inverse or forward modelling of the travel times of crustal and mantle phases using the ray theory approach. The modelling codes differ in terms of model parameterization, data used for modelling, regularization of the result, etc. It is helpful to know the capabilities, advantages and limitations of the code used compared to others.This work compares some popular 2D seismic modelling codes using the dataset collected along the seismic wide-angle profile DOBRE-4, where quite peculiar/uncommon reflected phases were observed in the wavefield.The ~505 km long profile was realized in southern Ukraine in 2009, using 13 shot points and 230 recording stations. Double PMP phases with a different reduced time (7.5–11 s) and a different apparent velocity, intersecting each other, are observed in the seismic wavefield. This is the most striking feature of the data. They are interpreted as reflections from strongly dipping Moho segments with an opposite dip. Two steps were used for the modelling. In the previous work by Starostenko et al. (2013), the trial-and-error forward model based on refracted and reflected phases (SEIS83 code) was published. The interesting feature is the high-amplitude (8–17 km) variability of the Moho depth in the form of downward and upward bends. This model is compared with results from other seismic inversion methods: the first arrivals tomography package FAST based on first arrivals; the JIVE3D code, which can also use later refracted arrivals and reflections; and the forward and inversion code RAYINVR using both refracted and reflected phases. Modelling with all the codes tested showed substantial variability of the Moho depth along the DOBRE-4 profile. However, SEIS83 and RAYINVR packages seem to give the most coincident results.
{"title":"Various Approaches to Forward and Inverse Wide-Angle Seismic Modelling Tested on Data from DOBRE-4 Experiment","authors":"T. Janik, P. Środa, W. Czuba, D. Lysynchuk","doi":"10.1515/acgeo-2016-0084","DOIUrl":"https://doi.org/10.1515/acgeo-2016-0084","url":null,"abstract":"The interpretation of seismic refraction and wide angle reflection data usually involves the creation of a velocity model based on an inverse or forward modelling of the travel times of crustal and mantle phases using the ray theory approach. The modelling codes differ in terms of model parameterization, data used for modelling, regularization of the result, etc. It is helpful to know the capabilities, advantages and limitations of the code used compared to others.This work compares some popular 2D seismic modelling codes using the dataset collected along the seismic wide-angle profile DOBRE-4, where quite peculiar/uncommon reflected phases were observed in the wavefield.The ~505 km long profile was realized in southern Ukraine in 2009, using 13 shot points and 230 recording stations. Double PMP phases with a different reduced time (7.5–11 s) and a different apparent velocity, intersecting each other, are observed in the seismic wavefield. This is the most striking feature of the data. They are interpreted as reflections from strongly dipping Moho segments with an opposite dip. Two steps were used for the modelling. In the previous work by Starostenko et al. (2013), the trial-and-error forward model based on refracted and reflected phases (SEIS83 code) was published. The interesting feature is the high-amplitude (8–17 km) variability of the Moho depth in the form of downward and upward bends. This model is compared with results from other seismic inversion methods: the first arrivals tomography package FAST based on first arrivals; the JIVE3D code, which can also use later refracted arrivals and reflections; and the forward and inversion code RAYINVR using both refracted and reflected phases. Modelling with all the codes tested showed substantial variability of the Moho depth along the DOBRE-4 profile. However, SEIS83 and RAYINVR packages seem to give the most coincident results.","PeriodicalId":50898,"journal":{"name":"Acta Geophysica","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2016-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/acgeo-2016-0084","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67091193","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}
Calculation results of the variations of dynamic and thermal process parameters in geospace plasma during the 13–15 November 2012, magnetic storm (MS) over Kharkov are presented. The calculations were based on experimental data obtained on the Kharkov incoherent scatter radar, single in the European mid-latitudes. Calculations showed that during the MS there took place an increase, by modulus, of the values of vertical component of transfer velocity, due to ambipolar diffusion, up to a factor of 1.4–2.1. During the MS there took place a decrease of the values of energy input to the electron gas by about 20–35%. During the main phase of MS, the heat flux density transferred by electrons increased up to a factor of 2–2.5. Results of estimates of the zonal component electric field value Ey are presented. During the MS the value of Ey was −9.5 mV/m. The vertical component of plasma velocity due to electromagnetic drift vEB has been calculated.
{"title":"Dynamic and Thermal Processes in the Mid-Latitude Ionosphere over Kharkov, Ukraine (49.6° N, 36.3° E), During the 13–15 November 2012 Magnetic Storm: Calculation Results","authors":"M. Lyashenko","doi":"10.1515/acgeo-2016-0087","DOIUrl":"https://doi.org/10.1515/acgeo-2016-0087","url":null,"abstract":"Calculation results of the variations of dynamic and thermal process parameters in geospace plasma during the 13–15 November 2012, magnetic storm (MS) over Kharkov are presented. The calculations were based on experimental data obtained on the Kharkov incoherent scatter radar, single in the European mid-latitudes. Calculations showed that during the MS there took place an increase, by modulus, of the values of vertical component of transfer velocity, due to ambipolar diffusion, up to a factor of 1.4–2.1. During the MS there took place a decrease of the values of energy input to the electron gas by about 20–35%. During the main phase of MS, the heat flux density transferred by electrons increased up to a factor of 2–2.5. Results of estimates of the zonal component electric field value Ey are presented. During the MS the value of Ey was −9.5 mV/m. The vertical component of plasma velocity due to electromagnetic drift vEB has been calculated.","PeriodicalId":50898,"journal":{"name":"Acta Geophysica","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2016-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/acgeo-2016-0087","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67091424","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}
Pore structure and mineral matrix elastic moduli are indispensable in rock physics models. We propose an estimation method of pore structure and mineral moduli based on Kuster-Toksöz model and Biot’s coefficient. In this technique, pore aspect ratios of five different scales from 100 to 10−4 are considered, Biot’s coefficient is used to determine bounds of mineral moduli, and an estimation procedure combined with simulated annealing (SA) algorithm to handle real logs or laboratory measurements is developed. The proposed method is applied to parameter estimations on 28 sandstone samples, the properties of which have been measured in lab. The water saturated data are used for estimating pore structure and mineral moduli, and the oil saturated data are used for testing these estimated parameters through fluid substitution in Kuster-Toksöz model. We then compare fluid substitution results with lab measurements and find that relative errors of P-wave and S-wave velocities are all less than 5%, which indicates that the estimation results are accurate.
{"title":"An Estimation Method of Pore Structure and Mineral Moduli Based on Kuster-Toksöz (KT) Model and Biot’s Coefficient","authors":"Da Peng, Cheng Yin, Hu Zhao, Wei Liu","doi":"10.1515/acgeo-2016-0108","DOIUrl":"https://doi.org/10.1515/acgeo-2016-0108","url":null,"abstract":"Pore structure and mineral matrix elastic moduli are indispensable in rock physics models. We propose an estimation method of pore structure and mineral moduli based on Kuster-Toksöz model and Biot’s coefficient. In this technique, pore aspect ratios of five different scales from 100 to 10−4 are considered, Biot’s coefficient is used to determine bounds of mineral moduli, and an estimation procedure combined with simulated annealing (SA) algorithm to handle real logs or laboratory measurements is developed. The proposed method is applied to parameter estimations on 28 sandstone samples, the properties of which have been measured in lab. The water saturated data are used for estimating pore structure and mineral moduli, and the oil saturated data are used for testing these estimated parameters through fluid substitution in Kuster-Toksöz model. We then compare fluid substitution results with lab measurements and find that relative errors of P-wave and S-wave velocities are all less than 5%, which indicates that the estimation results are accurate.","PeriodicalId":50898,"journal":{"name":"Acta Geophysica","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2016-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/acgeo-2016-0108","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67092286","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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