ORIGINAL_ARTICLE
-
Iran is located in the arid and semi-arid zone of the earth. The presence of many limestone
formations as well as suitable geological conditions have resulted in the formation and
development of vast areas of karstic terrains in this country. As the result of diminishing water
supplies, contamination of alluvial aquifers, increase in population and industrial and agricultural development, the study and exploration of karstic water resources have become increasingly
important. In this study, by using different geophysical logs, the lithology, fracture pattern and points of inflow and outflow in the karstic water wells of Ghasr-e Ghomshe, located in Zagros
region, south-west Iran have been analysed. The logs used are; gamma, neutron-neutron, electric,
gamma-gamma, caliper, temperature, flowmeter and fluid-resistivity. The study of some of the
hydrogeological parameter, especially hydraulic head, shows that the ground water supplies in this karstic area have been mainly confined in two reservoirs with different hydraulic heads. The
difference between the hydraulic heads of these two groung water reservoirs, which are separated
by impermeable marly layers, is approximately determined to be 170 meters
https://jesphys.ut.ac.ir/article_13102_82cfcf890bd368ddecf813f045308565.pdf
1999-04-21
aquifers
geophysical logs
hydraulic head
hydrogeology
Karst
well logging
احمد
زمانی
86541326
1
AUTHOR
احمد حسینی
رچی
41715359
2
LEAD_AUTHOR
ORIGINAL_ARTICLE
-
The effect of frequency on P- and S-wave velocity dispersions on a few samples of sandstones
and limestones from Chabahar region in both dry and saturated states under low axial stress has been studied. Three pairs of piezoelectric transducers with the central frequencies of 63, 200 and
500 kHz are employed to measure P-wave velocity dispersions. Two pairs of similar transducers but with the central frequencies of 33 and 100 kHz have been used for S-wave velocity dispersion
measurements.
The results obtained in these experiments show that P-wave velocities in both dry and saturated states increase with increase of the frequency. However, the rate of velocity increase
form 63 kHz to 200 kHz is greater than that from 200 kHz to 500 kHz. It is also observed that
S-wave velocities increase with increase of the frequency, although in a few cases the velocity
dispersions was not normal. For both P and S waves the velocity dispersions in saturated samples
are greater than dry ones.
A dispersion equation has been used to extract quality factors (Q) from two sets of velocity
data
(
63 and 200 kHz for P waves and 33 and 100 kHz for S waves
.
samples are found to be greater than those for water saturated rocks
https://jesphys.ut.ac.ir/article_13103_99ae6ea95089db0145fb10f9863b076a.pdf
1999-04-21
compressional and shear wave velocities
quality factors
velocity dispersion
مجید نبی
بیدهندی
1
AUTHOR
محمود
فتحی
57457124
2
LEAD_AUTHOR
ORIGINAL_ARTICLE
-
The occurrence of groundwater in hard rocks is very much different from that in granular
media, being highly irregular due to varriable subsurface geology and hydrogeology. The
accumulation and movement of water in such an area, are governed by primary and secondary
porosity (mainly due to weathering, jointing and fracturing). It is cleafly known that the potential
water may reside preferentially in those regions where either weathering zone attains considerable thickness or where the fracturing, jointing is intense.
The square array technique is used to throw some light on this problem. The objective of this study is to apply the square array resistivity and chargeability techniques to aid the understanding
of the fracture behaviour of hard rocks in detph. Work by several researchers in square array resistivity show the usefulness of the techniques in such investigations. In this study we add the
square array chargeability to these methods, which have been conducted at Shahran in north-west of Tehran, Iran. The area have an undulating topography.
A useful parameter of anisotropic medium, known as the coefficient of anisotropy and the
mean resistivity indicates whether fractures are water saturated or not. The square array
technique having a profile with a station interval of 20 m and survey line vertical to the fault direction with a square length of 200 m were applied in the site. The profile at Shahran in
north-west of Tehran has survey line of 300 m long. The discharge rate of 13.5 m "3/hr for the exisiting well is consistent with our data.
The definitions for coefficient of anisotropy and mean resistivity were applied to the induced polarisation technique. Saturated fractures are indicated by high mean chargeability and high
coefficient of anisotropy in chargeability.
The square array resistivity and chargeability techniques made at Shahran show that
significant joints and fractures occur in these area which are saturated with water. These studies
further indicate that the intensity of fracturing may differ considerably both in the horizontal and
vertical directions in hard rock terrains.
https://jesphys.ut.ac.ir/article_13104_47300fa8210b8873d9b02b34e62b120a.pdf
1999-04-21
chargeability
Coefficient of anisotropy
Fracture
hard rocks
resistivity
square array
محمد کاظم
حفیظی
79858465
1
AUTHOR
جعفر
ولی
89136659
2
LEAD_AUTHOR
ORIGINAL_ARTICLE
-
In this paper a one - dimensional hydraulic model for katabatic winds in Tehran is presented.
Such winds, considering low-level inversions in urban areas, have important effects on air
pollution transport. The inputs of the model is acquired from climatic observations for this area. The model although simple, predicts the properties of the local winds within acceptable levels.
The maximum speed in its vertical profile occurs at about 1/4 of the depth of the katabatic wind.
The wind speed and temperature profiles of the flow are time dependent
https://jesphys.ut.ac.ir/article_13105_2dd440bbe0426def44f0296633db9344.pdf
1999-04-21
dynamic and hydraulic models
inversion
katabatic wind
عباسعلی علی اکبری
بیدختی
41242119
1
AUTHOR
تاج الدین بنی
هاشم
22915468
2
AUTHOR
مهدی
ثقفی
52491517
3
LEAD_AUTHOR
ORIGINAL_ARTICLE
-
The motion and behaviour of a Cut-Off Low centre are studied from baroclinic point of view. The development of a surface cyclone and associated Cut-Off Low formed at the east of the
Mediterranean Sea on the 20th February, 1997, is investigated, together with various parameters,
such as vertical motion and different types of vorticity, using a regular grid mesh of 19x15 points, at nine pressure levels, with constant 100 hPa intervals, from 1000 hPa to 200 hPa.
Results of the numerical computation, presented in diagrams, along with synoptical
reasonings show the development of the surface cyclone following the Cut-Off Low centre. It is
quite apparent that the advection of the positive potential vorticity into the deep trough, present at the east of the Mediterranean Sea, has been the cause of the Cut-Off Low centre formation. In
addition, because of the advection of the absolute vorticity together with the thickness advection,
the surface baroclinic waves have been altered so that positive (negative) advection caused to
strengthen (weaken) the waves.
https://jesphys.ut.ac.ir/article_13106_dc9d429150f43d006390588f09e1cdf1.pdf
1999-04-21
Cyclogenesis
forcing function
jet stream
Pattern
vorticity
تاج الدین بنی
هاشم
22915468
1
AUTHOR
حسین
اردکانی
25189957
2
AUTHOR
محمد
مرادی
moradim36@gmail.com
3
LEAD_AUTHOR
ORIGINAL_ARTICLE
-
The WWSSN long-period body waves of Golbaf and Sirch-Chaharfarsang destructive
earthquakes are analyzed in order to study their source characteristics. Rupture during the Golbaf earthquake initiated in the epicentral area at the northwest part of the activated fault
segment and propagated unilaterally to southeast. The observed complex waveforms of Sirch-Chaharfarsang earthquake are explained in terms of a multiple source consist of at least two
major subevents. Rupture during its source process, initiated near the southeast of its associated surface trace where the first subevent with pure reverse mechanism had occurred and propagated
mainly northwest where the second subevent with a significant lateral component occurred. Regarding the source mechanism of these earthquakes, the shear strain produced by the first
earthquake around the epicentral area of the second earthquake is calculated. Significant accumulation of shear strain preceded the occurrence of the 'second earthquake. This sudden
increase of shear strain, caused by the first earthquake, had an influence on the occurrence of the
second earthquake. Extensive observations might reveal more details about the future activity.
https://jesphys.ut.ac.ir/article_13107_b3defa1c9511d7505055e4367f84c9ec.pdf
1999-04-21
Golbaf and Sirch-Chaharfarsang earthquakes
Rupture process
seismicity and seismotectonics of south-east Iran
source mechanism
strain field
محمدرضا
قیطانچی
57329365
1
LEAD_AUTHOR
ORIGINAL_ARTICLE
-
Moment tensor inversion was carried out to invert the source mechanism of the Ms = 7.3
May 10, 1997, Qaen-BiIjand, Iran, earthquake. Waveforms of long-period P-wave recorded by a number of stations of the Global Digital Seismic Network (GDSN) on vertical components were
used in the inversion. The inverted result shows one nodal plane of right-lateral strike-slip faulting and another of left-lateral strike-slip faulting. From the geological data, tectonic settings, field
observations and epicentral distribution of early aftershocks, the nodal plane striking in the azimuth of 3120 is preferred as fault plane. 1\vo principal axes lie almost horizontally and one
vertical. These show that the region is subject to a strong compression and pushing from Eurasia plate through the Afghanistan and Turkmenistan stable blocks. An average dislocation of jj Rj 70
em and a stress drop of 2.1 MPa can be inferred.
https://jesphys.ut.ac.ir/article_13108_476511c7ccb570ff19e4c4e9248daa32.pdf
1999-04-21
Focal mechanism
Moment tensor inversion
principal stress axis
پروین
مظفری
15599652
1
AUTHOR
روئوفنگ
لیو
29117245
2
AUTHOR
جونگ لیانگ
وو
25498878
3
AUTHOR
یون تای
چن
75714752
4
LEAD_AUTHOR
ORIGINAL_ARTICLE
-
Using a sophisticated radiative transfer model, the biological UV radiation absorbed by
tropospheric ozone is compared to that absorbed by the same amount of stratospheric ozone for
various solar zenith angles (SZAs) and different skies. For solar zenith angles less than 60., the model results suggest that the addition of each 5 Dobson Unit (DU) ozone in the troposphere,
can offset the increase in erythemally-weighted UV (EER) radiation which is caused by 10 DU
ozone depletion in the stratosphere, if a typical cloud is present in the sky. Clouds and
non-absorbing aerosols were found to elevate the effectiveness of tropospheric ozone by
increasing the pathlength of the photons. In relation to ozone depletion in the stratosphere, a new index: which is called offset index: (OFI) is introduced. This index: can quantify the changes in
tropospheric constituents (e.g., ozone, cloud, aerosol, etc.) which is required to be added into the
troposphere in order to offset the increased biologically UV (e.g.,UVB, EER, cataract, keratitis)
are computed by the model for a typical latitude.
resulted from a real ozone depletion in the stratosphere. The offset indices of cloud and aerosols
https://jesphys.ut.ac.ir/article_13109_cd7d0565117cea034d1f0bafb16c5ccc.pdf
1999-04-21
erythema
offset index
ozone depletion
surface UVB
tropospheric ozone
علی اکبر سبزی
پرور
23416255
1
LEAD_AUTHOR