Institute of Geophysics, University of TehranJournal of the Earth and Space Physics2538-371X26220000621--12906FAJournal Article19700101Ground vibration is a serious outcome of open pit mine blastings. The effect of the azimuth of measuring point to the blasted block, the effect of
starting point and the direction of blast movement on the vibration of the surrounding area of the blasted block are considered. In Sarcheshmeh
Copper Mine in SE Iran, seismic waves generated by 14 blasts have been recorded by 6-8 digital seismographs with three component seismometers.
Seismic data from vertical, tangential and radial component seismograms
were processed and analyzed in the frequency and time domains.
By the convolution of seismograms related to one single blasthole with
the time series corresponding to two double blastholes we simulated seismograms for two double blastholes with delay time of 25 and 65 msec.
Results of the seismogram simulation were compared with seismic real data recorded by 3-C seismometer from double blastholes. Thereafter, the
accuracy of the method was confirmed. Then, we simulated seismograms related to several multi-row blastholes with various delays between holes
and rows. Quantifying the effect of location and azimuth of the measuring point as well as the direction of blast movement on simulation of
seismograms, the impact of them on the ground vibration was studied. It was shown that the minimum ground vibration is in a direction with the
azimuth of 180-225° with the free surface of the blasted block.Ground vibration is a serious outcome of open pit mine blastings. The effect of the azimuth of measuring point to the blasted block, the effect of
starting point and the direction of blast movement on the vibration of the surrounding area of the blasted block are considered. In Sarcheshmeh
Copper Mine in SE Iran, seismic waves generated by 14 blasts have been recorded by 6-8 digital seismographs with three component seismometers.
Seismic data from vertical, tangential and radial component seismograms
were processed and analyzed in the frequency and time domains.
By the convolution of seismograms related to one single blasthole with
the time series corresponding to two double blastholes we simulated seismograms for two double blastholes with delay time of 25 and 65 msec.
Results of the seismogram simulation were compared with seismic real data recorded by 3-C seismometer from double blastholes. Thereafter, the
accuracy of the method was confirmed. Then, we simulated seismograms related to several multi-row blastholes with various delays between holes
and rows. Quantifying the effect of location and azimuth of the measuring point as well as the direction of blast movement on simulation of
seismograms, the impact of them on the ground vibration was studied. It was shown that the minimum ground vibration is in a direction with the
azimuth of 180-225° with the free surface of the blasted block.https://jesphys.ut.ac.ir/article_12906_ed64525494c72c10b9a7b5bd5bf82f3c.pdfInstitute of Geophysics, University of TehranJournal of the Earth and Space Physics2538-371X26220000621--12907FAJournal Article19700101A method of three-dimensional ray tracing and model parameterization is presented. The method is intended for propagation media with a
laterally varying velocity and thickness. Developed algorithm in this study (FAIT-3D) is based on the shooting ray tracing technique and solves 3-D
Eikonal equations using finite difference methods. While rays are being traced, the traveltimes and their partial derivatives with respect to
parameters of the model grids are calculated. In order to evaluate the
adequacy and robustness of the algorithm, two synthetic models with several in-line profiles were used. The results surpassed our expectations in
several ways.A method of three-dimensional ray tracing and model parameterization is presented. The method is intended for propagation media with a
laterally varying velocity and thickness. Developed algorithm in this study (FAIT-3D) is based on the shooting ray tracing technique and solves 3-D
Eikonal equations using finite difference methods. While rays are being traced, the traveltimes and their partial derivatives with respect to
parameters of the model grids are calculated. In order to evaluate the
adequacy and robustness of the algorithm, two synthetic models with several in-line profiles were used. The results surpassed our expectations in
several ways.https://jesphys.ut.ac.ir/article_12907_8bf52b4fad6f2887050befbc0a64c5d1.pdfInstitute of Geophysics, University of TehranJournal of the Earth and Space Physics2538-371X26220000621--12908FAJournal Article19700101Magnitude has played a particular role in the realistic description of global seismicity. Most studies in earthquake seismology use magnitude
data as a guide to the strength of an earthquake. So biases in magnitude estimates, caused by any effect, directly affect the result of any study in
which magnitude data is used. In this study, efficiency of using different formulae and depth-distance calibration terms are examined.
Applications of the MsR-P formula and new depth-distance terms to the ISC dataset, show that the estimated Ms and mb values are
independent of distance, and provide unbiased estimates of Ms and mb in comparison with commonly-used Prague formula and Gutenberg-Richter
terms. Comparison of standard deviation of Ms values for single events using the MsR-P and _rague formulae show that the _-P standard deviations are consistently smaller than those of Prague formula. Also
standard deviations of estimated mb values using the new depth-distance terms are smaller than standard deviations of estimated values using Gutenberg-Richter terms. Estimated Ms and mb values using _-P
formula and the new depth-distance terms reduce overlap in Ms:mb criterion for underground explosions and earthquakes. The study reported here confirms the need to modify the formula for Ms calculation and depth-distance correction terms for mb calculation, which are used by
global agencies such as ISC and NEICMagnitude has played a particular role in the realistic description of global seismicity. Most studies in earthquake seismology use magnitude
data as a guide to the strength of an earthquake. So biases in magnitude estimates, caused by any effect, directly affect the result of any study in
which magnitude data is used. In this study, efficiency of using different formulae and depth-distance calibration terms are examined.
Applications of the MsR-P formula and new depth-distance terms to the ISC dataset, show that the estimated Ms and mb values are
independent of distance, and provide unbiased estimates of Ms and mb in comparison with commonly-used Prague formula and Gutenberg-Richter
terms. Comparison of standard deviation of Ms values for single events using the MsR-P and _rague formulae show that the _-P standard deviations are consistently smaller than those of Prague formula. Also
standard deviations of estimated mb values using the new depth-distance terms are smaller than standard deviations of estimated values using Gutenberg-Richter terms. Estimated Ms and mb values using _-P
formula and the new depth-distance terms reduce overlap in Ms:mb criterion for underground explosions and earthquakes. The study reported here confirms the need to modify the formula for Ms calculation and depth-distance correction terms for mb calculation, which are used by
global agencies such as ISC and NEIChttps://jesphys.ut.ac.ir/article_12908_9dd350ec9c603c24c8dfa05341e5a759.pdfInstitute of Geophysics, University of TehranJournal of the Earth and Space Physics2538-371X26220000621--12909FAJournal Article19700101In this paper an attempt was made to introduce the procedure of thermal data logging in shallow wells and to show the correlation between
the thermal anomaly and shallow tectonic events in the study area. In this context thermal well logging data of the Salman Farsi dam site is chosen.
The dam site area is located in south central part of Zagros mountain near to Shiraz, Iran. Thermal diagrams versus depth were performed and
preliminary considerations were made using least squares method. This
study showed a considerable thermal anomaly at the dam site. In this stage the Fourier thermal function was used to determine the thermal gradient
of the anomalous zone. Indications of geological informations revealed that the temperature anomaly may be attributed to hot ground water
impressed by a local minor fault.In this paper an attempt was made to introduce the procedure of thermal data logging in shallow wells and to show the correlation between
the thermal anomaly and shallow tectonic events in the study area. In this context thermal well logging data of the Salman Farsi dam site is chosen.
The dam site area is located in south central part of Zagros mountain near to Shiraz, Iran. Thermal diagrams versus depth were performed and
preliminary considerations were made using least squares method. This
study showed a considerable thermal anomaly at the dam site. In this stage the Fourier thermal function was used to determine the thermal gradient
of the anomalous zone. Indications of geological informations revealed that the temperature anomaly may be attributed to hot ground water
impressed by a local minor fault.https://jesphys.ut.ac.ir/article_12909_e96909d190684f425a0838d7bb053bd3.pdfInstitute of Geophysics, University of TehranJournal of the Earth and Space Physics2538-371X26220000621--12910FAJournal Article19700101In this paper, the velocity values of shear and compressional elastic waves of Phyllite limestone samples obtained both theoretically and
practically are compared. These rock samples were performed in cubic shape.
At the room pressure and temperature, the velocity values for these
samples were measured using the first arrival times of elastic waves along
the mentioned samples. The frequency of compressional waves was 63kHz and that for shear waves was 33 kHz. The velocity values of compressional
and shear waves for different incident angles such as 0, 30, 45, 60 and 90 degress between the receiver and the transducer were measured. In the
theoretical stage, the crack density and dynamically Lame's constants were computed using Budiansky and O'Connel (1974) theory. Then, the
theoretical velocity values of the same samples were calculated based on Hudson (1980) theory.
The obtained results showed that a good correlation exists between the calculated and the measured data for the samples with low crack density.
While for the samples with a high crack density the correlation is poor when the incident angles were at 30, 45 and 60 degrees. This difference
between theory and measurements might be attributed to the presence of inclusions and inhomogeneity in the rock samples.In this paper, the velocity values of shear and compressional elastic waves of Phyllite limestone samples obtained both theoretically and
practically are compared. These rock samples were performed in cubic shape.
At the room pressure and temperature, the velocity values for these
samples were measured using the first arrival times of elastic waves along
the mentioned samples. The frequency of compressional waves was 63kHz and that for shear waves was 33 kHz. The velocity values of compressional
and shear waves for different incident angles such as 0, 30, 45, 60 and 90 degress between the receiver and the transducer were measured. In the
theoretical stage, the crack density and dynamically Lame's constants were computed using Budiansky and O'Connel (1974) theory. Then, the
theoretical velocity values of the same samples were calculated based on Hudson (1980) theory.
The obtained results showed that a good correlation exists between the calculated and the measured data for the samples with low crack density.
While for the samples with a high crack density the correlation is poor when the incident angles were at 30, 45 and 60 degrees. This difference
between theory and measurements might be attributed to the presence of inclusions and inhomogeneity in the rock samples.https://jesphys.ut.ac.ir/article_12910_2eb33a0dc04f6466fc1bec81a6c58d0a.pdfInstitute of Geophysics, University of TehranJournal of the Earth and Space Physics2538-371X26220000621--12911FAJournal Article19700101For studying Gold-Arsenic mineralisation in Shirmard region, we have used aeromagnetic data. After processing the data and applying regional
correction, we plotted the total and residual magnetic maps of the region. These maps with respect to the state of magnetic anomaly contours, specify
the existence of a fault in the north of region as well as magnetic bodies in the surface of the region. For obtaining more information. different filters
such as downward continuation, upward continuation, vertical derivative and reduction to the magnetic pole have been applied for determining the
location of deep and shallow magnetic bodies in the region.
Then we determined the average depth of shallow and deep bodies in
the region by forming power density spectrum data. The existence of great aeromagnetic anomaly in this region, variety of mineralisation and
paragenesis of Zarshoran and Aghdareh mineral regions, proves the necessity of economical geology studies. Composed and simultaneous study
of this region with respect to the observed correlation in aeromagnetic interpretation between this region and dispersed mineral signs in around,
have been considered as studical model. In this search we have tried to
offer a correct and rational model by using accurate software and desert examinations simultaneously.For studying Gold-Arsenic mineralisation in Shirmard region, we have used aeromagnetic data. After processing the data and applying regional
correction, we plotted the total and residual magnetic maps of the region. These maps with respect to the state of magnetic anomaly contours, specify
the existence of a fault in the north of region as well as magnetic bodies in the surface of the region. For obtaining more information. different filters
such as downward continuation, upward continuation, vertical derivative and reduction to the magnetic pole have been applied for determining the
location of deep and shallow magnetic bodies in the region.
Then we determined the average depth of shallow and deep bodies in
the region by forming power density spectrum data. The existence of great aeromagnetic anomaly in this region, variety of mineralisation and
paragenesis of Zarshoran and Aghdareh mineral regions, proves the necessity of economical geology studies. Composed and simultaneous study
of this region with respect to the observed correlation in aeromagnetic interpretation between this region and dispersed mineral signs in around,
have been considered as studical model. In this search we have tried to
offer a correct and rational model by using accurate software and desert examinations simultaneously.https://jesphys.ut.ac.ir/article_12911_6af147f9649a7b9d10da4efe0444d361.pdfInstitute of Geophysics, University of TehranJournal of the Earth and Space Physics2538-371X26220000621--12912FAJournal Article19700101Darband and Golabdareh watersheds are located in the north of Tehran with a combined area of 33 km2. In July 1987, they exprienced a sever
flood that caused immense damages to the northern part of Tehran and claimed number of lives. The objective of the present study is to
investigate the said flood as well as flood frequency in the region. Unfortunately, the existing dischargegauging stations have short records
and there are not enough measurements from past floods. Because of the above problem, rainfall-runoff simulation was identified as the appropriate
way to analyze flood peaks and hydro graph. Among the different models for this kind of simulation, HEC1, HYMO, rational and matrix models
were selected for the purposed simulations. The results show better performance of matrix model. For the flood of July 1987, this model estimated peak flood equal to 356 m3/s.Darband and Golabdareh watersheds are located in the north of Tehran with a combined area of 33 km2. In July 1987, they exprienced a sever
flood that caused immense damages to the northern part of Tehran and claimed number of lives. The objective of the present study is to
investigate the said flood as well as flood frequency in the region. Unfortunately, the existing dischargegauging stations have short records
and there are not enough measurements from past floods. Because of the above problem, rainfall-runoff simulation was identified as the appropriate
way to analyze flood peaks and hydro graph. Among the different models for this kind of simulation, HEC1, HYMO, rational and matrix models
were selected for the purposed simulations. The results show better performance of matrix model. For the flood of July 1987, this model estimated peak flood equal to 356 m3/s.https://jesphys.ut.ac.ir/article_12912_00f1ea96e3341727c850541e0be4c6e9.pdfInstitute of Geophysics, University of TehranJournal of the Earth and Space Physics2538-371X26220000621--12913FAJournal Article19700101This paper is focused on the effect of the severest recorded EI-Nino on Iran climatic situation. The effect of the 1982-83 EI-Nino on temperature
and precipitation is very considerable. The average temperature during the period is much lower than normal and the precipitation is considerably
high. Because the EI-Nino is a periodic and somewhat predictable event, examining the behavior of such parameters during the occurance of the
event will help the prediction of the climatic situation of our country. The investigation shows high negative temperature anomaly and positive
precipitation onomaly during the period. Also an annual lag in minimum temperature and maximum precipitation can be seen clearly, although the
lag in maximum temperature is not so considerable. The contrast of the winter monsoon stream and south or southwestern stream because of the
event produce high gradients of isobars on Iran. The strengthening and shifting of monsoon toward Iran could be seen in the summer monsoon
which results in warmer summers during the period.This paper is focused on the effect of the severest recorded EI-Nino on Iran climatic situation. The effect of the 1982-83 EI-Nino on temperature
and precipitation is very considerable. The average temperature during the period is much lower than normal and the precipitation is considerably
high. Because the EI-Nino is a periodic and somewhat predictable event, examining the behavior of such parameters during the occurance of the
event will help the prediction of the climatic situation of our country. The investigation shows high negative temperature anomaly and positive
precipitation onomaly during the period. Also an annual lag in minimum temperature and maximum precipitation can be seen clearly, although the
lag in maximum temperature is not so considerable. The contrast of the winter monsoon stream and south or southwestern stream because of the
event produce high gradients of isobars on Iran. The strengthening and shifting of monsoon toward Iran could be seen in the summer monsoon
which results in warmer summers during the period.https://jesphys.ut.ac.ir/article_12913_6dcb784ea9bfad6e1a52019916c22fd6.pdfInstitute of Geophysics, University of TehranJournal of the Earth and Space Physics2538-371X26220000621--12914FAJournal Article19700101The ellipsoidal Stokes boundary-value problem is used to compute the geoidal heights. The low degree part of the geoidal heights can be
represented more accurately by global geopotential models. So the disturbing potential is splitted into a low-degree reference potential and a
higher degree potential. To compute the low-degree part, the global geopotential model is used and for the high-degree part, the ellipsoidal
Stokes integral is used. I present an effective method to remove the singularity of the spheroidal and spheroidal ellipsoidal Stokes functions
around the computational point. Finally, the numerical results ofsolving the spheroidal ellipsoidal Stokes integral is shown.The ellipsoidal Stokes boundary-value problem is used to compute the geoidal heights. The low degree part of the geoidal heights can be
represented more accurately by global geopotential models. So the disturbing potential is splitted into a low-degree reference potential and a
higher degree potential. To compute the low-degree part, the global geopotential model is used and for the high-degree part, the ellipsoidal
Stokes integral is used. I present an effective method to remove the singularity of the spheroidal and spheroidal ellipsoidal Stokes functions
around the computational point. Finally, the numerical results ofsolving the spheroidal ellipsoidal Stokes integral is shown.https://jesphys.ut.ac.ir/article_12914_1c903d94dd92d4db65cf7f4444999b3d.pdf