IRANIAN GEOPHYSICS CONFERENCE | Year:2006 | دوره:12 |Papers Count:43

VARIOUS PROBLEMS CAUSED BY THE PRESENCE OF GROUNDWATER IN AREA NO. 1 OF GOL-E- GOHAR IRON ORE MINE, HAVE MADE MINING EXPERTS SEEK APPROPRIATE METHODS FOR PREVENTING THE FLOW OF GROUNDWATER INTO THE MINE PIT. DUE TO THE EXPECTED NEGATIVE INFLUENCE OF SUBSURFACE WATER ON THE MINING ACTIVITIES IN AREA NO. 3 OF THIS MINE, A SUITABLE DRAINAGE SYSTEM SHOULD BE DESIGNED AND ESTABLISHED BEFORE COMMENCEMENT OF MINING ACTIVITIES.GEOELECTRICAL INVESTIGATIONS USING RESISTIVITY METHOD WERE CARRIED OUT IN THE AREA TO DETERMINE GROUNDWATER CONDITIONS IN THE AREA. TWENTY-FIVE RESISTIVITY SOUNDINGS WITH MAXIMUM ELECTRODE SPACING OF 1400M WERE PERFORMED IN THE AREA. A SQUARE GRID OF 500×500 M WAS SET UP TO COVER THE WHOLE AREA.ONE-DIMENSIONAL INTERPRETATION OF THE SOUNDING DATA SHOWED THE DEPTH TO WATER TABLE TO BE 40-60M WITH AN AVERAGE THICKNESS OF 26-35M FOR THE WATER-BEARING FORMATION. IT WAS ALSO INFERRED FROM THE SOUNDING DATA INTERPRETATIONS THAT THE RESISTIVITY OF THE WATER-BEARING FORMATION WAS IN THE RANGE OF 12-26WM, INDICATING HIGH ELECTRICAL CONDUCTIVITY OF GROUNDWATER, INTERPRETED TO BE DUE TO HIGH SALINITY AND CONCENTRATION OF TOTAL DISSOLVED SOLIDS (TDS) IN THE GROUNDWATER.

ESTIMATION OF NEUTRON LOGS FROM OTHER LOGS PROVIDES DETERMINATION OF ARTIFICIAL NEUTRON LOGS IN WELLS WITHOUT NEUTRON LOG. APPLICATION OF ARTIFICIAL NEURAL NETWORKS SUCH AS PREDICTION AND SIMULATION IS NOTABLE. SOME NEUTRON LOGS MIGHT BE LOST, THUS IN THIS STUDY WE USE NEURAL NETWORK AND TWO LOGS (DENSITY AND SONIC) TO PRODUCE ARTIFICIAL NEUTRON LOGS. A NETWORK INCLUDES FOUR LAYERS (ONE INPUT LAYER, TWO HIDDEN LAYERS AND ONE OUTPUT LAYER) WAS DESIGNED.

THE MULTICHANNEL ANALYSIS OF SURFACE WAVES METHOD (MASW) IS A NONDESTRUCTIVE SEISMIC METHOD TO EVALUATE PAVEMENT THICKNESS AS WELL AS TO EVALUATE LINEAR ELASTIC MODULUS OF GROUND AND MATERIALS UNDER PAVEMENT. IT ANALYSIS DISPERSION PROPERTIES OF CERTAIN TYPES OF SEISMIC SURFACE WAVES (FUNDAMENTAL MODE RAYLEIGH WAVES) PROPAGATING HORIZONTALLY ALONG THE SURFACE OF MEASUREMENT DIRECTLY FROM IMPACT POINT TO RECEIVERS. IT GIVES THE SHEAR-WAVE VELOCITY (VS) INFORMATION. WHEN SURFACE WAVE ARE UTILIZED TO DEDUCE A NEAR-SURFACE SHEAR-WAVE VELOCITY (VS) PROFILE (VS VERSUS DEPTH), THE ANALYSIS RELIES ON THE ACCURATE CALCULATION OF PHASE VELOCITIES FOR THE HORIZONTALLY TRAVELING FUNDAMENTAL-MODE RAYLEIGH WAVE. DECOMPOSITION OF A MULTICHANNEL RECORD INTO A TIME VARIABLE-FREQUENCY FORMAT, ALLOW EACH FREQUENCY COMPONENT TO BE SEPARATELY AND CONTINUOUSLY DISPLAYED (SWEPT FREQUENCY RECORD, SFR). SOME EXAMPLES FROM REAL SEISMIC DATA VERIFY THE MASW METHOD DESCRIBED HERE AND SFR METHOD EXTRACTING OF MULTICHANNEL DISPERSION CURVES.

THE RATE OF OZONE IS ALWAYS CHANGING. THESE VARIATIONS ARE DUE TO CHEMICAL AND DYNAMICAL FACTORS. THIS PAPER DISCUSSES THE RELATIONSHIP BETWEEN THE DAILY TOTAL COLUMN OZONE CHANGES AND THE WEATHER CONDITION OVER ISFAHAN IN 2004. TO INVESTIGATE THE RELATIONSHIP BETWEEN THE DAILY TCO AND DYNAMICAL CONDITION, THE ATMOSPHERIC PARAMETERS IN UPPER LAYER ARE DISCUSSED AT WHICH THE DAILY OZONE DEVIATIONS ARE STATISTICALLY SIGNIFICANT.

THIS RESEARCH AN ATTEMPT TO INVESTIGATE THE KINDS OF BLOCKING SYSTEMS OVER ATLANTIC AND PACIFIC OCEANS AS SYNOPTIC AND INTRODUCE; ALSO ATTEMPTS TO INVESTIGATE CYCLOGENESIS PHENOMENA OVER MEDITERRANEAN SEA, AND SPECIALLY IN THE EAST OF MEDITERRANEAN SEA, THAT THEIR EFFECTS INFLUENCE OVER IRAN'S REGION. AT THE FIRST STEP OF STUDY, MEDITERRANEAN TOPOGRAPHY, LOCAL MEDITERRANEAN WINDS AND CYCLOGENESIS HAVE STUDIED; THEN STRUCTURE AND TYPES OF EXISTING BLOCKING SYSTEMS ON SYNOPTIC WEATHER MAPS HAVE INTRODUCED WITH FIGURES.

WE PRESENT IMPACT-INDUCED CONVECTION MODELS IN THE MOON THAT EXPLAIN THE FORMATION OF LUNAR MARE BASALT, AND THE LONG DURATION OF THE BASALTIC FLOW. A LARGE PROJECTILE THAT PRODUCES AN IMBRIUM-SIZE IMPACT BASIN CAN INDUCE THREE STAGE OF MELTING AT DIFFERENT DEPTHS. THE FIRST OCCURS NEAR THE SURFACE, BY STRONG HEATING OF THE PROJECTILE AND TARGET THAT RESULTS IN MELTING AND VAPORIZATION OF THE MAJOR PART OF THE PROJECTILE AND NEAR-SURFACE PART OF THE TARGET. THIS RAPID MELTING DOES NOT CREATE MARE BASALT. THE SECOND MELTING ARISES FROM THE SUDDEN REDUCTION OF THE PRESSURE IN THE UPPER MANTLE DUE TO EXCAVATION OF THE BASIN. THE ASCENDING UPPER MANTLE MATERIAL IN THE PROCESS OF ISOSTATIC ADJUSTMENT IN RESPONSE TO THE EXCAVATION PARTIALLY MELTS BY DECOMPRESSION WITHIN LESS THAN A FEW MYR AFTER THE IMPACT. THE POSSIBLE RELATED VOLCANISM CANNOT EXPLAIN BASALTIC FLOW ON THE MOON THAT LASTED ABOUT 800 MYR. THE LOCAL IMPACT-INDUCED PERTURBATIONS, HOWEVER, TRIGGER GLOBAL-SCALE CONVECTION, AND A LARGE PLUME FROM LOWER MANTLE ASCENDS DIRECTLY BENEATH THE IMPACT BASIN. THIS CONVECTION CAUSES THE THIRD STAGE OF MELTING IN THE MANTLE AND PRODUCES WELL OVER 107 KM 3 OF MARE BASALT THAT GIVE RISE TO SUBSTANTIAL MARE FLOODING. WE INVESTIGATE THE EFFECTS OF AN IMPACT ON THE THERMAL EVOLUTION OF THE MOON AND MELT PRODUCTION IN THE MANTLE, USING CONVECTION CALCULATIONS IN AN AXI-SYMMETRIC CYLINDRICAL COORDINATE SYSTEM. THE MODELS HAVE TEMPERATURE-DEPENDENT VISCOSITY, AND TIME DEPENDENT HEAT SOURCES ARISING FROM DECAY OF RADIOACTIVE MATERIALS. THE MANTLE IS ALLOWED TO MELT AS IT CROSSES THE SOLIDUS TEMPERATURE AND PARTIAL MELTING IS CALCULATED. WE CONSIDER TWO DIFFERENT MODELS, PERMEABLE AND IMPERMEABLE. FIVE DIFFERENT VISCOSITY MODELS ARE EXAMINED, WHERE THE RATIO BETWEEN THE VISCOSITY AT THE SURFACE AND AT THE BOTTOM OF THE COMPUTATION DOMAIN IS 100, 500, 1000, 1500 AND 2000, RESPECTIVELY. THE PERMEABLE MODEL WITH VISCOSITY CONTRAST OF 1000 CAN EXPLAIN THE OBSERVED AMOUNT OF BASALTIC FLOW AS WELL AS THE DURATION OF THE VOLCANIC ERUPTION.

MINE WASTES OR GANGUES ASSOCIATED WITH VALUABLE MINERALS IN ORES ARE USUALLY SEPARATED BEFORE OR DURING MINERAL PROCESSING IN DIFFERENT STAGES OF CRUSHING AND ORE CONCENTRATION. THESE WASTE MATERIALS ARE THEN DUMPED IN AN AREA CLOSE TO THE MINE OR MINERAL PROCESSING PLANT. LEAKING SOLUTIONS FROM THESE DUMPS CONTAIN VARIOUS CHEMICAL COMPONENTS AND ARE CONSIDERED AS AN IMPORTANT SOURCE OF SOIL AND GROUNDWATER CONTAMINATIONS. MANY FACTORS SUCH AS PRECIPITATION, CAUSE MORE POLLUTANTS TO PERCOLATE UNDERGROUND LAYERS AND INCREASE THE EXTENT OF SUBSURFACE CONTAMINATION IN RECENT YEARS, GEOPHYSICAL TECHNIQUES, ESPECIALLY ELECTRICAL METHODS, HAVE BEEN SUCCESSFULLY APPLIED IN THE INVESTIGATION OF CONTAMINATIONS DUE TO MINE WASTES AND TAILINGS. ACCURACY, HIGH SPEED AND SIGNIFICANT REDUCTION IN EXPENSES ARE THE MOST DOMINANT ADVANTAGES OF THESE NON-INVASIVE METHODS. GEOELECTRICAL PROFILING AND SOUNDING SURVEYS WILL RESULT IN THE DETERMINATION OF THE LATERAL AND VERTICAL EXTENT OF CONTAMINATIONS, RESPECTIVELY. THIS PAPER DISCUSSES THE ADVANTAGES OF ELECTRICAL METHODS IN ENVIRONMENTAL STUDIES OF MINING ACTIVITIES. A CASE STUDY OF THE APPLICATION OF THE METHOD IS ALSO PRESENTED.

IN A NUMERICAL STUDY, A MODEL IS USED TO INVESTIGATE THE IMPACT OF THE ADDITION OF SEA-SALT AEROSOL PARTICLES ON THE EVOLUTION OF MARINE STRATOCUMULUS CLOUD. THE MODEL USED CALCULATES THE MICROPHYSICAL AND CHEMICAL DEVELOPMENT OF AN INPUT AEROSOL SPECTRUM (AT 99% RH) AS THE AIR PARCEL IN WHICH THEY RESIDE IS SUBJECTED TO ADIABATIC COOLING AS IT IS FORCED TO RISE UP THROUGH THE LAYER BETWEEN CLOUD BASE AND CLOUD TOP. THE VARIATIONS OF MICROPHYSICAL PARAMETERS WITH HEIGHT ABOVE CLOUD BASE HAVE BEEN EXAMINED FOR SEVERAL DIFFERENT UPDRAUGHT VELOCITIES, CLOUD BASE TEMPERATURES AND INPUT DRY AEROSOL NUMBER AND SIZE DISTRIBUTION. THE RESULTS SHOW THAT THE MICROPHYSICAL STRUCTURE OF LAYER CLOUDS WAS STRONGLY AFFECTED BY THE PHYSICAL PROPERTIES OF THE AEROSOL PARTICLES FROM WHICH THE CLOUD DROPLETS GREW. FURTHER MODEL RUNS WITH ELEVATED SEA SALT AEROSOL CONCENTRATIONS SHOWED THE CLOUD ALBEDO EFFECTS RELATED TO THESE PERTURBATIONS IN BACKGROUND MARINE AEROSOL MAY CONSTITUTE A NEGATIVE FEEDBACK TO GLOBAL WARMING. AN IMPLICATION IS THAT THE INTRODUCTION OF SEA-SALT AEROSOL INTO CLOUD, PERHAPS BY MECHANICALLY PRODUCING SEA-SALT AT THE SURFACE, MAY BE A METHOD FOR OFFSETTING GLOBAL WARMING. IN THIS STUDY THE MODELLED MICROPHYSICAL PROPERTIES OF STRATOCUMULUS CLOUD HAVE BEEN EXAMINED. DATA OBTAINED FROM A DIFFERENTIAL MOBILITY PARTICLE SIZER (DMPS) AND AN ACTIVE SCATTERING AEROSOL SPECTROMETER PROBE-MODEL X (ASASP-X) IN THE FORM OF A TYPICAL MARITIME AEROSOL SIZE DISTRIBUTION FROM THE ACE-2 EXPERIMENT HAVE BEEN USED AS INPUT TO A MODEL.

INFORMATION ABOUT THE ERRORS IN THE OBSERVATIONS IS ESSENTIAL TO SOLVE ANY INVERSE PROBLEM; OTHERWISE, IT IS IMPOSSIBLE TO ESTIMATE TRUE MODEL. IN PRACTICE, HOWEVER, ESPECIALLY WITH SINGLE REALIZATION OF EXPERIMENT, ONE SELDOM HAS A DIRECT ESTIMATE OF THE DATA ERRORS. HERE WE EXPLOIT THE TRADE-OFF BETWEEN DATA PREDICTION AND MODEL OR DATA STRUCTURE TO DETERMINE BOTH MODEL-INDEPENDENT AND MODEL BASED ESTIMATES OF THE NOISE CHARACTERISTICS FROM A SINGLE REALIZATION OF THE DATA. NOISE ESTIMATES WITH OTHER INFORMATION ABOUT MODEL PARAMETERS ARE THEN USED TO CONSTRUCT CONFIDENCE INTERVALS ABOUT THE FINAL MODEL THAT ARE TIGHTER THAN PRIOR INFORMATION AND AGREE WITH PRIOR CONSTRAINTS. WE ILLUSTRATE OUR METHODS WITH SYNTHETIC EXAMPLE OF VERTICAL SEISMIC PROFILING (VSP).

THE GEOELECTRICAL SOUNDING WITH THE LINEAR ARRAY IS ONE THE GEOPHYSICAL TECHNIQUES WHICH IS FREQUENTLY USED FOR UNDERGROUND WATER RESOURCE EXPLORATION AND ENGINEERING SITES INVESTIGATION. IN THE OCCASION WHERE NO SOUND GEOLOGICAL DATA EXIST TO INDICATE A HORIZONTAL LAYERED EARTH STRUCTURE OR ITS STRUCTURE IS NOT HOMOGENEOUS AND ALSO IS ANISOTROPIC, APPLICATION AND INTERPRETATION OF ITS MODELING RESULTS MAY MISLEAD INTERPRETER. IN THIS PAPER THE IMPORTANCE OF SQUARE ARRAY RESISTIVITY SOUNDING, WHICH IS LESS POPULAR THAN TO THOSE LINEAR ARRAYS, IS EXPLAINED BY NUMERICAL MODELING AND INTERPRETATION OF THE ACQUIRED DATA. THE RESULTS OF THE PRESENT STUDY SHOW THE SUB-SURFACE STRUCTURES OF THE EARTH ARE ANISOTROPIC IN THE MOST OCCASIONS AND CONSEQUENTLY THE OBTAINED RESULTS OF THE LINEAR ARRAY FOR RESISTIVITY SOUNDING ARE NOT CORRECT. THIS IS TRUE EVEN IN THE CASES WHERE THE SPACING BETWEEN THE SITES IS SMALL ENOUGH. WHEREAS, THE RESULTS OF THE IMPLEMENTED SQUARE ARRAY SOUNDING ARE ACCURATE ENOUGH TO EXPLAIN THE EARTH STRUCTURES BENEATH EACH SITE. HENCE, IN THESE SITUATIONS IT IS RECOMMENDED TO USE SQUARE ARRAY FOR GEOELECTRICAL SOUNDING AS IT LESS AFFECTED BY ORIENTATION OF THE SUBSURFACE STRUCTURES.

SPECTRAL DECOMPOSITION IS A POWERFUL TOOL FOR ANALYSIS OF SEISMIC DATA. FOURIER TRANSFORM DETERMINES THE FREQUENCY CONTENTS OF A SIGNAL. BUT FOR ANALYZING OF A NON-STATIONARY SIGNAL, 1-D TRANSFORM TO FREQUENCY DOMAIN IS NOT SUFFICIENT. IN EARLY YEARS, TRANSFORMING OF SEISMIC TRACES INTO TIME AND FREQUENCY DOMAIN WAS DONE VIA WINDOWED FOURIER TRANSFORM, SO CALLED A SHORT TIME FOURIER TRANSFORM (STFT). THE LENGTH OF THE SELECTED WINDOW IN STFT WAS CONFINED THE RESOLUTION OF THE RESULTS IN TIME-FREQUENCY DOMAIN. CONTINUOUS WAVELET TRANSFORM (CWT) WAS A REMEDY TO SOLVE THIS PROBLEM BY USING THE SCALEABLE WAVELETS. THE SCALE IN CWT IS RELATED TO THE FREQUENCY BANDWIDTH OF THE WAVELET AND ITS CONVERSION TO FREQUENCY YIELD TIME-FREQUENCY MAP WHICH IS COMPARABLE TO THE TIME-FREQUENCY MAP OBTAINED FROM STFT. IN THIS STUDY, WE APPLIED CWT ON A SEISMIC SECTION AND EXTRACTED A SINGLE FREQUENCY SEISMIC SECTION FROM THE RESULTED CUBE. THE EXTRACTED SECTIONS WERE USED TO DETECT LOW FREQUENCY SHADOW OF THE HYDROCARBON RESERVES OVER THE STUDY AREA AS WELL AS ANALYZING THE EXISTING THIN LAYERS ON A SYNTHETIC SEISMIC SECTION.

THE S TRANSFORM IS A TYPE OF TIME-FREQUENCY TRANSFORM. IT IS BASED ON A MOVING AND SCALABLE LOCALIZING GAUSSIAN WINDOW. IT IS POSSIBLE TO DESIGN A TIME AND FREQUENCY DEPENDED FILTER USING THE S TRANSFORM. IN THIS STUDY WE DESIGNED A WEIGHTED FILTER BASED ON THE S TRANSFORM. ACCORDING TO OUR RESULTS, THE DESIGNED FILTER IS SUITABLE FOR NOISE ATTENUATION FROM NMO CORRECTED GATHERS WITH STATIC SHIFTS UP TO 0.03 S. IN ORDER TO MAKE THE FILTER APPLICABLE TO THE PRE NMO CORRECTED DATA, A GENERALIZED S TRANSFORM WAS USED. THE NOISE REMOVAL RESULTS FROM WEIGHTED FILTER BASED ON THE GENERALIZED S TRANSFORM SURPASSED OUR EXPECTATIONS.

MEASUREMENT OF GROSS A, GROSS B ACTIVITIES AND COSMOGENIC BERYLLIUM‐7 (7BE ) CONCENTRATIONS WERE MADE BOTH DAILY AND WEEKLY DURING 2001, 2002, 2003 AND 2004 FROM SAMPLES OF ATMOSPHERIC AEROSOLS FILTERED FROM THE AIR AT TEHRAN NUCLEAR RESEARCH CENTER (35O 41’ N) AND ZAHEDAN (28O 29’ N). THE DATA ARE SUFFICIENTLY NUMEROUS TO ALLOW US TO EXAMINE VARIATIONS IN TIME AND THROUGH THESE MEASUREMENTS WE HAVE ESTABLISHED ATMOSPHERE. THE AIR CONCENTRATIONS OF GROSS B AND GROSS A ACTIVITIES AND 7BE CONCENTRATION DISPLAYED A LOGNORMAL DISTRIBUTION DURING THE STUDY PERIOD. BOTH OF B ACTIVITIES AND 7BE HAVE MAXIMUM CONCENTRATIONS DURING WARM MID-YEAR MONTHS. IN THIS WORK, THE DATA ON CONCENTRATION AND METEOROLOGICAL DATA HAVE BEEN MADE USE OF IN ORDER TO DETERMINE A MODEL FOR GROSS A AND GROSS B AND 7BE, RESPECTIVELY. THE MODEL CAN BE USED TO ESTIMATE THAT PART OF THE TREND IN GROSS B AND IN 7BE LEVELS THAT CAN BE ACCOUNTED FOR BY TRENDS IN LOCAL METEOROLOGY. WE DIDN’T FIND ANY RELATION BETWEEN GROSS A AND METEOROLOGY PARAMETERS. A SATISFACTORY AGREEMENT BETWEEN THE RESULTS OF THE MODEL AND THE MEASUREMENTS WAS HIGHLIGHTED.

THREE-DIMENSIONAL (3D) THREE-COMPONENT (3C) SHALLOW SEISMIC REFRACTION SURVEYS WERE RECORDED OVER A SHEAR ZONE AT TWO SITES ASSOCIATED WITH DRYLAND SALINITY IN THE SPICERS CREEK CATCHMENT, NEAR DUBBO IN SOUTHEASTERN AUSTRALIA. THE SEISMIC DATA WERE RECORDED WITH THE AUSTRALIAN NATIONAL SEISMIC IMAGING RESOURCES (ANSIR) 360-TRACE, ARAM24 SEISMIC SYSTEM AND IVI MINIVIBE MODEL T-15000.THE BROAD OBJECTIVE OF THIS STUDY WAS TO USE SEISMIC REFRACTION METHOD TO MAP IN DETAIL A SHEAR ZONE, WHICH IS ASSOCIATED WITH THE SALINATION. SEISMIC REFRACTION METHOD WAS SELECTED BECAUSE OF THEIR POTENTIAL ABILITY TO PROVIDE GREATER LATERAL RESOLUTION OF THE NARROW VERTICAL SHEAR ZONE, THAN IS CURRENTLY THE NORM WITH ELECTRICAL AND ELECTROMAGNETIC METHODS. THIS SITUATION WAS CONFIRMED WITH A NUMBER OF RESISTIVITY DEPTH IMAGES AND MAGNETIC IMAGES GENERATED AS PART OF STUDY.THE SEISMIC REFRACTION SURVEYS IN THE STUDY AREA SHOW THAT THE SHEAR ZONE OCCURS AS A NARROW REGION WITH LOW VELOCITIES AND INCREASED DEPTHS OF WEATHERING. THE CROSS-CUTTING FEATURES ASSOCIATED WITH THE MAJOR SHEAR ZONE SHOW THAT SALINE GROUNDWATER CAN DISCHARGE AT THE SURFACE WHERE INCREASED VOLUMES OF GROUNDWATER OCCUR AT THE INTERSECTION OF DIFFERENT SETS OF SHEARS. THIS MODEL PROVIDES A USEFUL EXPLANATION FOR THE DISCONTINUOUS OCCURRENCE OF SALINATION ALONG THE MAJOR SHEAR ZONE.

SEISMIC IMAGING IS A TWO-STEP PROCESS OF VELOCITY ANALYSIS AND MIGRATION. AS THE VELOCITY FUNCTION BECOMES MORE COMPLEX, THE TWO STEPS BECOME MORE INTERDEPENDENT. IN COMPLEX DEPTH-IMAGING PROBLEMS, VELOCITY ESTIMATION AND MIGRATION ARE OFTEN APPLIED ITERATIVELY. TO ASSURE THAT THIS ITERATIVE IMAGING PROCESS CONVERGES TO A SATISFACTORY MODEL, IT IS CRUCIAL THAT THE MIGRATION AND VELOCITY ESTIMATION PROCEDURES ARE CONSISTENT WITH EACH OTHER.IN THIS PAPER, VELOCITY ANALYSIS AND IMAGING ARE COMBINED IN ONE STEP AND MIGRATION WILL BE USED AS A VELOCITY ANALYSIS TOOL. SO A METHOD SIMILAR OF SILVA & WANG (2002) FOR ITERATIVE PSDM-TC STACK USED FOR IMAGING BOTH SYNTHETIC AND REAL DATA.

RESISTIVITY IS ON OF THE MOST POPULAR GEOPHYSICAL METHODS USED FOR GROUND-WATER EXPLORATION. IT IS SOMETIMES USED WITH THE INDUCED POLARIZATION METHOD TO HAVE A BETTER INTERPRETATION. THE MAIN OBJECTIVE OF THIS PAPER IS TO SHOW HOW THE RESULTS OF THE NUMERICAL MODELING OF THE GEOPHYSICAL DATA CAN SERVE AS USEFUL TOOLS TO PREPARE A HYDRO-GEOLOGICAL MODEL OF THE AQUIFER FOR THE PURPOSE OF THE PROSPEROUS DRILLING. TO ACHIEVE THE GOAL, THE ACQUIRED GEOPHYSICAL DATA OF A RELATIVELY VAST PLAIN, LOCATED IN THE 40 KM OF NORTH EAST OF SHAHROOD CITY, ARE FIRST VERIFIED AND CORRECTED AND THEN FED TO THE COMPUTER PROGRAMS FOR THE ONE AND TWO-DIMENSIONAL (1D AND 2D) INVERSE MODELING. THE OBTAINED RESULTS OF THE MODELING WERE THEN USED TO PROVIDE A HYDROGEOLOGICAL MODEL OF THE PLAIN IN THE FORM OF CONTOUR MAP OF GROUND- WATER SURFACE. THIS MAP HELPED US TO FIND THE SUITABLE AREA WITHIN THE STUDIED ZONE FOR THE FUTURE DRILLING.

THROUGH LABORATORY AND FIELD MEASUREMENTS OF SOME SELECTED SAMPLES OF THE STUDY AREA AND BY NUMERICAL CALCULATION, A GEOPHYSICAL MODEL AT THE TANGHUPING DISTRICT WAS BUILT. GRADIENT AND POLE-DIPOLE DUAL-FREQUENCY IP WERE USED TO ACQUIRE DATA. INTERPRETATION OF THE PROCESSED DATA SHOWS A PROSPEROUS GOLD MINERALIZATION ZONE IN THE EAST OF THE STUDY AREA.

SURFACE LAYER IN SOUTH OF KHORASAN PROVINCE HAS BEEN STUDIED TO FORECAST MINIMUM TEMPERATURE AND ISSUE EARLY WARNING FOR PREVENTION OF CROP FROSTING IN THE AREA. AT FIRST EFFECTIVE PARAMETERS IN SURFACE LAYER TEMPERATURE VARIATION WHERE STUDIED, THEN NECESSARY METEOROLOGICAL DATA FROM WEATHER STATIONS (BIRJAND, GHAEN AND GONABAD) IN THE STATISTICAL PERIOD WERE ANALYZED AND BY USING THEORETICAL MODELS OF BRUNT AND GROEN MINIMUM TEMPERATURE FOR CLEAR AND CALM NIGHT FORECAST THE RESULT WAS THAT GROEN MODEL WAS MORE EXACT THAN THE BRUNT MODEL. BUT GROEN MODEL IN HIGH HUMID CONDITION IS NOT ACCEPTABLE.

THE S TRANSFORM IS A TIME-FREQUENCY TRANSFORM. IT IS BASED ON A MOVING AND SCALABLE LOCALIZING GAUSSIAN WINDOW. THE S TRANSFORM CAN OBTAIN TIME-FREQUENCY DISTRIBUTION OF SEISMIC SECTIONS IN ORDER TO ANALYSIS THE FREQUENCY DEPENDENCY OF SIGNAL VERSUS TIME (DEPTH). THIS PARAMETER WILL BE A ROBUST ATTRIBUTE FOR DETERMINING AND MONITORING HYDROCARBON RESERVOIRS. IN THIS STUDY, THE S TRANSFORM HAS BEEN APPLIED BOTH ON SYNTHETIC AND REAL SEISMIC SECTIONS AND PROVED ITS EFFICIENCY IN DETECTION OF HYDROCARBON GATHERING ZONE USING LOW FREQUENCY SHADOW ZONE IDEA.

GEOMAGNETIC FIELD VARIES WITH TIME AND SPACE IN A COMPLICATED WAY. TIME VARIATIONS CONSIST OF SECULAR AND TRANSIENT VARIATIONS. ONE OF THE TRANSIENT VARIATIONS IS NAMED GEOMAGNETIC BAY, WHICH LOOKS LIKE A MAP OF AN INDENTATION IN A COASTLINE OR GAUSSIAN CURVE. THE DURATION OF BAY CAN BE FROM A FEW MINUTES TO A FEW HOURS. THE BAYS GENERALLY OCCUR ON SOLAR QUIET DAYS ACCOMPANY WITH PI1 AND PI2 MICROPULSATIONS. THE BAYS ARE TWO-STAGE EVENTS; THE EARLY STAGE IS TRIGGER BAY AND THE SECOND IS MAIN BAY. THIS TYPE OF VARIATION (AND ALL VARIATIONS) INDUCES ELECTRIC CURRENTS IN THE EARTH. THE INDUCED ELECTRIC CURRENTS GIVE RISE IN THEIR TURN TO AN INTERNAL COMPONENT OF THE MAGNETIC VARIATIONS OBSERVED AT THE SURFACE. THE RATIO OF THE PARTS OF THE MAGNETIC FIELD OF INTERNAL AND EXTERNAL ORIGIN IS A MEASURE OF THE RESPONSE, AND IS DEPENDENT ON BOTH THE EXTERNAL CURRENT SYSTEM AND THE DISTRIBUTION OF THE ELECTRICAL CONDUCTIVITY WITHIN THE EARTH. USING THIS METHOD, THE ELECTRICAL CONDUCTIVITY OF THE EARTH CAN BE DETERMINED FOR VARIOUS DEPTHS ACCORDING TO THE PERIOD OF THE MAGNETIC VARIATIONS. IN THIS PAPER, IT IS MADE A STATISTICAL STUDY OF BAYS RECORDED AT TEHRAN GEOMAGNETIC OBSERVATORY FOR THE PERIOD OF 1971-80 ACCORDING TO THE TIME OF THEIR OCCURRENCE, INTENSITY AND DIRECTION. WE HAVE ALSO TAKEN IN CONSIDERATION THE GEOMAGNETIC SEASONS. MAXIMUM NUMBERS OF BAYS OCCUR AT MIDNIGHT WITH MODERATE INTENSITY AND POSITIVE DIRECTION. MOST OF BAYS TAKE PLACE IN EQUINOX AND DECEMBER SOLSTICE. RETURN CURRENTS ARE PREDOMINANT CURRENT SYSTEM. THE DELAY TIME BETWEEN THE ONSETS OF TWO STAGES LIE IN RANGE 10-30 MINUTES. THE RELATION BETWEEN THE NUMBERS OF THE SUNSPOTS AND THE BAYS IS INVERSELY PROPORTIONAL.

RESERVOIR PROPERTIES SUCH AS POROSITY COULD BE PREDICTED, PRECISELY, BY INTEGRATION OF SEISMIC DATA AND INVERSION RESULT. IN THIS STUDY, FIRST BY USING 3D SEISMIC DATA, HORIZON INTERPRETATIONS AND WELL LOGS, 3D ACOUSTIC IMPEDANCE MODEL OF RESERVOIR WAS GENERATED. THEN SOME SINGLE ATTRIBUTES EXTRACTED FROM SEISMIC DATA. AFTER THAT LINEAR STEP WISE REGRESSION METHOD WAS USED TO GENERATE SEISMIC MULTI-ATTRIBUTES. LATER, THE THREE LAYERED ARTIFICIAL NEURAL NETWORK, WITH THREE NODES IN INPUT LAYER, EIGHT NODES IN HIDDEN LAYER AND ONE IN OUTPUT DESIGNED. FINALLY, 3D POROSITY MODEL ESTIMATED APPLYING NEURAL NETWORK, SEISMIC MULTI-ATTRIBUTES AND WELL LOGS.

THE RESISTIVITY METHOD IS ONE THE GEOPHYSICAL TECHNIQUES THAT IS FREQUENTLY USED FOR GROUNDWATER AND ENGINEERING EXPLORATION. THE LINEAR ELECTRODE ARRAYS ARE MOSTLY USED TO MEASURE THE RESISTIVITY OF THE EARTH STRUCTURES. AMONG THE NONLINEAR ARRAYS, THE SQUARE ARRAY IS THE ONE THAT RARELY USED IN PRACTICE IN SPITE OF ITS ABILITIES. THE MAIN OBJECTIVE OF THIS PAPER IS TO SHOW THE CAPABILITIES OF THIS METHOD IN DETECTION OF WATER BEARING FRACTURES COVERED BY SEDIMENTS. THE RESULTS OF RESISTIVITY MEASUREMENT ALONG TWO PROFILES CLEARLY INDICATE THE PRESENCE OF TWO WATER FILLED FRACTURE ZONES IN THE NORTH WEST OF SHAHROOD CITY, WHICH THE LOCATION ONE OF THESE ZONES IS NEARLY COINCIDENT WITH A PUBLIC WATER WELL.

THE GRAVITY AND MAGNETIC SURVEYS HAVE BEEN CARRIED OUT TO DETECT THE POSSIBLE OIL TRAPS, TO DETERMINE THE APPROXIMATE DEPTH OF SEDIMENTS AND TO VERIFY THE PRESENCE OF THE INTRUSIVE MASSES, FAULTS AND SALT PLUGS IN ROODAN AREA IN BANDAR ABBAS PROVINCE. THE FIELD MEASUREMENTS WERE PERFORMED IN A 2000 SQUARED METER AREA AT 2400 STATIONS. THE BOUGUER ANOMALY AND TOTAL INTENSITY CONTOUR MAPS WERE PREPARED AND INTERPRETED WHEN THE NECESSARY CORRECTIONS WERE DONE ON OBSERVED DATA. A TWO-DIMENSIONAL INVERSE MODELING (SHEET MODEL) WAS CARRIED OUT ON THE GRAVITY DATA. THE RESULTS OBTAINED FROM THE INTERPRETATION AND MODELING REVEALED THE PRESENCE OF AN ANTICLINE NAMED "A" WHICH IS IMPORTANT FOR OIL EXPLORATION PURPOSE AND IT IS LOCATED IN AN APPROXIMATE DEPTH OF 3 KM. THE INTERPRETATION OF THE MAGNETIC MAPS VERIFIED THE ABSENCE OF INTRUSIVE MASSES AND PROVED THE CONSIDERABLE THICKNESS OF SEDIMENTS. FURTHERMORE, THERE IS NO ANY EVIDENCE TO CONFIRM THE PRESENCE OF ANY SALT PLUG IN THE STUDY AREA. DUE TO THE COMPLEX GEOLOGY OF THE AREA AND THE PRESENCE OF OIL SEEPS IN THE STUDY AREA, MORE DETAILED STUDIES ARE HOWEVER REQUIRED USING THE OTHER EXPLORATION METHODS.

IN THIS RESEARCH, IN ORDER TO CONSIDER THE FREEZINGS WHICH OCCURRED IN EKBATAN (HAMEDAN) STATION, MINIMUM DAILY TEMPERATURES OF THIS STATION WERE STUDIED, THAT IN GENERALLY FREEZINGS WERE DIVIDED TO 3 LEVELS: WEAK-FREEZING, MIDDLE-FREEZING AND INTENSE-FREEZING.THEN, WE DETERMINED THE RANGE OF TEMPORAL CHANGES AND THE ABUNDANCE OF THE FREEZING. ALSO WE HAVE TRIED TO INTRODUCE AN EMPIRICAL FORMULA WHICH CAN FORECAST THE DATE OF FIRST AUTUMNAL FREEZING ACCORDING TO THE DATE OF LAST SPRING FREEZING. BY CALCULATING DIFFERENT STATISTICAL PARAMETERS, PROBABILITY OF OCCURRENCE THE TEMPERATURE THRESHOLDS BETWEEN -15 TO 0 (OC) WERE DETERMINED FOR DIFFERENT MONTHS .IN ADDITION TO THIS, BY DIVIDING THE YEAR TO 36 DIFFERENT PERIODS OF TEN DAYS, WE HAVE TRIED TO CALCULATE TEMPERATURE OF DIFFERENT PROBABILITY PERCENTS.

DOWNBURSTS ARE SMALL-SCALE, SHORT-LIVED AND ENERGETIC EVENTS IN THE ATMOSPHERE. DISTINCTIVE FEATURES ASSOCIATED WITH DOWNBURST ARE: A SUDDEN DROP IN TEMPERATURE, SUDDEN INCREASE IN WIND SPEED, WIND SHIFT, PRESSURE RISE AND HUMIDITY INCREMENT. IN THIS STUDY, A PHYSICAL MODEL OF DOWNBURSTS HAS BEEN PRESENTED.VERTICAL RELEASE OF KNOWN VOLUME DENSE FLUID IS SIMULATED IN AN ISOTROPIC AND A DENSITY STRATIFIED ENVIRONMENT. AS SOON AS THE RELEASED FLUID REACHES THE SURFACE, IT FORMS THE SHAPE OF A VORTEX RING AND SPREADS OUT IN ALL DIRECTIONS LIKE GRAVITY CURRENT. TYPICAL FROUDE NUMBERS OF THE FLOW IN 0.7 THE STRUCTURE OF THE FLOW IN MONITORED BY CONDUCTIVITY PROBES SHOWING INHOMOGENEOUS TURBULENT STRUCTURE. SUCH AS VERTICALLY MOVING FLOW IN THE ATMOSPHERE. CAN LEAD TO DANGER TO FLYING AIRCRAFTS NEAR THE GROUND AND HENCE MUST BE STUDIED AND MONITORED NEAR THE AIRPORTS.

THE GRAVITY AND MAGNETIC SURVEYS HAVE BEEN CARRIED OUT TO INVESTIGATE THE SUBSURFACE OIL TRAPS IN QUM AREA, TO EXPLORE ANY HIDDEN GEOLOGICAL FEATURE OF QUM FORMATION AND TO DETECT ANY INTRUSIVE MASS AND FAULTS. THE FIELD MEASUREMENTS WERE PERFORMED AT 2059 STATIONS. THE BOUGUER ANOMALY AND TOTAL INTENSITY CONTOUR MAPS WERE PREPARED AND INTERPRETED WHEN THE NECESSARY CORRECTIONS WERE DONE ON OBSERVED DATA. THE NECESSARY FILTERING METHODS WERE THEN USED TO ELIMINATE THE EFFECTS OF REGIONAL STRUCTURES AND TO ENHANCE THE LOCAL ANOMALIES, WHICH ARE INTERESTED IN HYDROCARBON EXPLORATION. FOR MODELING PURPOSE, GRAV2DC, A 2.5 DIMENSIONAL MODEL WAS USED TO PERFORM A FORWARD MODELING ON THE GRAVITY DATA. THE MAGNETIC DATA WAS ALSO MODELED USING A 2.5 DIMENSIONAL FORWARD MODELING AND INVERSION SOFTWARE CALLED MAG2DC. THE RESULTS SHOW THAT ALTHOUGH THE PRESENCE OF AN ANTICLINE NAMED "A" IS IMPORTANT FOR OIL EXPLORATION PURPOSE AND IT IS LOCATED IN PROPER DEPTH, HOWEVER, THE MAGNETIC INTENSITY IS VERY HIGH ON A PART OF THIS ANOMALY. FURTHERMORE, IT IS ALSO AFFECTED BY SURROUNDING FAULTS. THEREFORE, THESE FEATURES DISQUALIFY ITS SIGNIFICANT FOR FURTHER EXPLORATION.

DECONVOLUTION IS ONE OF THE MOST IMPORTANT SEISMIC DATA PROCESSING STEPS WHICH IMPROVE THE QUALITY OF SEISMIC DATA. CLASSIC METHODS OF DECONVOLUTION CONSTRUCTED BASED ON ASSUMPTIONS WHICH VIOLATED IN REAL WORLD. NOISE FREE DATA IS ONE OF THE MENTIONED ASSUMPTIONS. USING OF HOPFIELD NEURAL NETWORK IN SEISMIC DECONVOLUTION TO ESTIMATE EARTH REFLECTIVITY IS ONE OF DECONVOLUTION METHODS. IN THIS PAPER, SENSITIVITY OF THIS METHOD TO NOISE AND FREQUENCY BAND OF SOURCE WAVELET IS ANALYZED. THIS METHOD ESTIMATES THE REFLECTIVITY SERIES IN TWO STAGES: 1. REFLECTIVITY LOCATION DETECTION, 2. REFLECTIVITY MAGNITUDE ESTIMATION. EVALUATION OF RESULTS SHOWS THAT, USING OF HOPFIELD NEURAL NETWORK FOR DECONVOLUTION IS NOT SENSITIVE TO NOISE AND SOURCE WAVELET FREQUENCY BAND.

A NEW IMPLEMENTATION OF THE NORMAL-MOVEOUT (NMO) CORRECTION IS DESCRIBED IN THIS PAPER THAT IS ROUTINELY APPLIED TO COMMON-MIDPOINT (CMP) REFLECTIONS PRIOR TO STACKING. THIS METHOD AUTOMATICALLY AVOIDS THE UNDESIRABLE STRETCH EFFECTS THAT ARE PRESENT IN CONVENTIONAL NMO (NMO STRETCH). UNDER THIS METHOD, A SIGNIFICANT RANGE OF LARGE OFFSETS, THAT WOULD NORMALLY BE MUTED IN THE CASE OF CONVENTIONAL NMO, CAN BE KEPT AND USED IN STACK. THE METHOD IMPROVES THE RESOLUTION OF CMP STACK. THE USE OF THIS METHOD IS ILLUSTRATED BY ITS APPLICATION TO SYNTHETIC AND REAL DATASETS.

IN THIS STUDY WE INVESTIGATE THE PRODUCTION AND MIGRATION OF MELT IN SUBDUCTION ZONES WITH THE AID OF A NUMERICAL SIMULATION. WE SOLVE THE GOVERNING EQUATIONS OF THE FLOW OF A FLUID MELT PHASE THROUGH A POROUS AND DEFORMING MANTLE ROCK. WE INVESTIGATE THE VOLUME OF MELT PRODUCED AND ITS SUBSEQUENT MOVEMENT UNDER A VARIETY OF CONDITIONS. WE FIND THAT THE NONLINEAR DEPENDENCE OF THE MANTLE ROCK PERMEABILITY ON ITS POROSITY IS THE DEFINING FACTOR IN THE TIME VARIATIONS OF MELT PRODUCTION AND THE PATTERN OF MIGRATION THROUGH THE MANTLE. FURTHERMORE, WE INVESTIGATE THE IMPORTANCE OF OTHER PARAMETERS, SUCH AS THE AGE OF THE SUBDUCTING PLATE, AND SUBDUCTION DIP AND VELOCITY.

ELECTRICAL SOUNDING INCORPORATING SCHLUMBERGER ARRAY IS ONE OF THE MOST COMMON GEOPHYSICAL TECHNIQUE, WHICH IS NORMALLY USED FOR THE EXPLORATION OF GROUNDWATER AQUIFERS. IN ORDER TO OBTAIN PROPER RESULTS OF THE ACQUIRED GEOELECTRICAL DATA, IT IS REQUIRED TO DO A NUMERICAL INVERSE MODELING IN AN APPROPRIATE MANNER TO DETERMINE THE SUBSURFACE LAYERS PARAMETERS. THE INVERSE MODELING CAN PROVIDE VALUABLE INFORMATION OF THE SUBSURFACE STRUCTURES HOWEVER; DUE TO SOME LIMITATIONS, A UNIQUE RESULT CANNOT BE PROVIDED. THIS PAPER AIMS TO SHOW HOW THE IMPROVED RESULTS CAN BE OBTAINED USING A SUITABLE INITIAL MODEL ALONG WITH PERFORMING A SMOOTH AND PARAMETRIC MODELING, TAKING TO CONSIDERATION THE CONCEPT OF EQUIVALENT MODELS. THE RESULTS OF AN ELECTRICAL SOUNDING NEARBY A WATER WELL AND ANALYSIS OF ITS EQUIVALENT MODELS INDICATE THAT THE RESULTS OF PARAMETRIC MODELING IS PRECISE ENOUGH PARTICULARLY FOR DETERMINATION OF WATER TABLE DEPTH.

INSINUATION OF IGNEOUS MASSIVE AMONG THE EOCENE VOLCANIC ROCKS IN SARCHESHME OF KERMAN REGION, WHILE ALTERATION THE REGION ROCKS, HAS MINERALIZATED COPPER, GENERALLY OF PORPHYRY TYPE IN THAT ZONE. THIS PROJECT TRIED TO ANALYSIS THE AERIAL GEOPHYSICS DATA OF THE REGION INCLUDING MAGNETOMETRY, RADIOMETRY, RESISTIVITY (935, 4600HZ), AND MAGNETIC GRADIENT WHILE INSPECTING EXPLORATION PATTERNS OF THIS DATA HAS INTEGRATION WITH PRINCIPAL COMPONENT ANALYSIS AND SELECTING PRIMARY PRINCIPAL COMPONENT OF THEM. ACCORDING TO THE PRIMARY PRINCIPAL COMPONENT PROPERTIES, EXPLORATION PATTERNS OF AERIAL GEOPHYSICS DATA OF THE REGION IS COVERD BY COMPONENT. IN THE NEXT STAGE BY DESIGNING A GIS OBTAINED DATA LAYERS HAS INTEGRATION BY USING THE FUZZY LOGIC AND POTENTIOMETRY MAP OF THE REGION TO PRESENT THE PROBABLE DEPOSITS FROM EXISTING INFORMATION, HAS PROVIDED.

TO GET A CONCEPT OF THE SPREAD AND DISTRIBUTION OF URANIUM MINERALIZATION IN A SELECTIVE SECTION, ONE OF THE FAST METHODS IS NATURAL GAMMA-RAY LOGS CORRELATION FOR BOREHOLES LOCATED AT THOSE SECTIONS. SO THE, DIGITAL GAMMA-RAY LOGS OF FOUR BOREHOLES LOCATED AT ONE PROFILE, IN KHOSHOUMI AREA IN CENTRAL IRAN, ARE PROCESSED AND ANALYZED. DIFFERENT PROCESSING METHODS WERE TESTED TO FIND THE BEST AND CLEAREST DELINEATION OF THIS SECTION. WITH REGARD TO THE FACT THAT MINERAL AND URANIUM MINERALIZATION DISTRIBUTION ARE LENTICULAR IN THIS AREA, THE PROCESS BASED ON INVERSE DISTANCE TO A POWER IS THE MOST SUITABLE METHOD IN COMPARISON WITH OTHER METHODS AND SHOWS THE BEST FIT WITH GEOLOGICAL OBSERVATIONS IN THE AREA.

AN INCREASE OR DECREASE IN THE PRECIPITATION INTENSITY COMPARED TO THE NORMAL CONDITIONS MAY LEAD TO A HIGHER RISK OF FLOODS OR A HIGHER PROBABILITY OF OCCURRENCE OF DROUGHT. KNOWLEDGE OF THE PROBABILITY DISTRIBUTION OF PRECIPITATION IS ESSENTIAL FOR THE MANAGEMENT OF WATER RESOURCES. SUCH KNOWLEDGE CAN BE ACHIEVED USING DYNAMICAL OR STATISTICAL APPROACHES. IN THE PRESENT ARTICLE THE PROBABILITY OF DIFFERENT DROUGHT STATES (VERY DRY, DRY, SEMIDRY, NORMAL, SEMI WET, WET, AND VERY WET) ARE CALCULATED BASED ON THE ANNUAL AND SEASONAL PRECIPITATION AMOUNTS IN GHAZVIN USING THE NORMAL DISTRIBUTION AND MARKOV CHAIN METHODS. THE RESULTS INDICATE THAT THE PROBABILITIES OF DROUGHT/WET STATES BASED ON ANNUAL AND SEASONAL PRECIPITATION DATA AS CALCULATED USING THE TWO METHODS ARE COMPARABLE. THE STATISTICAL EVALUATION OF THE RESULTS USING C2 , HOWEVER, REVEALS THAT THE MARKOV CHAIN METHOD IS SUPERIOR TO THE NORMAL DISTRIBUTION.

ENERGY RELEASED INDICATES AT THE MOST REGION ESTIMATED WITH AFTERSHOCKS. FOR INVESTIGATION AFTERSHOCKS, LOCAL STATION DATA OF IRAN AT 40 YEARS STUDIED. AFTERSHOCKS FIXED WITH PHYSICAL FORM. THE RESULT INDICATE AFTERSHOCK TIME FUNCTION OF POTENTIAL REGION, THE DISTRIBUTION OF AFTERSHOCKS SUGGEST THAT USE, OMORI, UTSU, MOGI AND KISSLINGER RELATIONS, THEN AFTERSHOCK REDUCE CURVES DRAW FOR 1962 BUIN-ZAHRA, 1968 DASHT-E-BAYAZ,1990 RUDBAR,1990 FORK, 1997 ARDABIL, 2002 AVAJ AND 2005 ZARAND EARTHQUAKE AFTERSHOCKS. FOR SEQUENCE INDICATED AFTERSHOCK CURRENT RATE. THE RESULT INDICATES PHYSICAL AND DYNAMICAL BEHAVIOR CRUST. WITH THIS STUDY FOR AFTERSHOCKS REDUCE MODELS AND CURVES, THE MODIFIED OMORI MODEL WAS BEST FITTED FOR THE LATER STAGE OF THE AFTERSHOCK SEQUENCE.

THE HYPOCENTERS OF ABOUT 3735 EARTHQUAKES RECORDED BY GLOBAL SEISMIC STATIONS DURING THE LAST 40 YEARS WERE ANALYZED. THE REGION OF STUDY WAS DIVIDED INTO SUB SQUARES OF EACH 0.5´0.5 DEGREE. THE ENERGY RELEASED FOR EACH EARTHQUAKE WAS EVALUATED FROM ENERGY MAGNITUDE RELATION AND THE ENERGY OF EARTHQUAKES IN EACH SQUARE FOR EACH TIME INTERVAL WERE SUM UP AND THE MAPS OF SEISMIC ENERGY RELEASED IN 4 TIME INTERVALS OF 10 YEARS BETWEEN 1965 AND 2004 AND 1 TIME INTERVAL FOR THE PAST 40 YEARS WERE PROVIDED AND OVER LAPPED ON THE FAULT MAP. THE TIME- FREQUENCY AND MAGNITUDE- FREQUENCY DIAGRAMS FOR IRAN WERE PROVIDED. THE GRAPH OF ACCUMULATED ENERGY RELEASED IN 5 YEARS INTERVALS FROM 1964 TO 2004 FOR ACTIVE ZONES IN IRAN WERE CALCULATED. AS EXPECTED, THE RATE OF SEISMIC ENERGY IN ZAGROS IS LARGER THAN OTHER PARTS OF IRAN. THE RESULT INDICATED THAT THE MOST PARTS OF IRANIAN PLATEAU WERE SEISMICALLY ACTIVE DURING THE PAST 40 YEARS. ALBORZ AND LUT REGIONS WERE SEISMICALLY ACTIVE, CHARACTERIZED BY SIGNIFICANT EARTHQUAKES. ZAGROS HAD A MORE REGULAR PATTERN OF SEISMIC ACTIVITY AND EXPERIENCED MODERATE AND SMALL EARTHQUAKES. THE DIFFERENT SEISMIC PATTERNS SUGGEST THAT THE PHYSICAL PROPERTIES OF FAULT SYSTEMS ARE DIFFERENT IN DIFFERENT REGIONS AND THE CRUST IS INHOMOGENEOUS IN IRANIAN PLATEAU. THE COMPARISON OF SEISMIC ENERGY MAPS INDICATES THAT THE SEISMIC GAPS IN EARLY INTERVALS WERE FILLED UP BY THE SEISMIC ACTIVITIES DURING THE FOLLOWING TIME INTERVALS.

TO STUDY THE SEISMICITY OF PAKISTAN AND INVESTIGATE THE CHARACTERISTICS OF THE 8TH OCTOBER 2005 DESTRUCTIVE EARTHQUAKE IN NORTH PAKISTAN, THE SOURCE PARAMETERS OF THE RECORDED EARTHQUAKES BY THE SEISMIC STATIONS IN THE WORLD DURING THE PAST 40 YEARS AS WELL AS THE RECENT EARTHQUAKE IN PAKISTAN AND IT’S AFTERSHOCKS WHERE COLLECTED. THEN THE EPICENTER DISTRIBUTION OF EARTHQUAKES WHERE OVER LAPPED ON THE FAULTS MAP IN THE MIDDLE EAST. FAULT PLANE SOLUTIONS OF 98 STRONG EARTHQUAKES IN PAKISTAN AND NEIGHBORING REGIONS IN AFGHANISTAN AND INDIA WERE DETERMINED BY THE POLARITY OF INITIAL P WAVES. IN NEXT STAGE, THE SEISMIC ENERGY RELEASED BY STRONG EARTHQUAKES IN THE REGION WAS DETERMINED FROM MAGNITUDE USING RICHTER RELATION OF MAGNITUDE -ENERGY IN EACH 0.5´0.5 SUB SQUARE AND PLOTTED ON THE FAULTS MAP OF THE REGION THE FAULT OFFSET OF THE MAIN EARTHQUAKE WAS CALCULATED TO BE 8 M, IT’S SOURCE DURATION WAS ABOUT 40 S AND IT CUASED A FAULTING ABOUT 120 KM. IT’S STRESS DROP WAS CALCULATED ABOUT 40 BAR. THE FAULT OFFSET OF THE STRONGEST AFTERSHOCK WAS CALCULATED TO BE 2.5 M, IT’S SOURCE DURATION WAS ABOUT 3 S AND IT CUASED A FAULTING ABOUT 10 KM. IT’S STRESS DROP WAS CALCULATED ABOUT 14 BAR. THE RESULT INDICATED THAT THE PAMIR- HINDU KUSH REGION WAS SEISMICALLY ACTIVE DURING THE PAST 40 YEARS WHICH RELEASED SIGNIFICANT SEISMIC ENERGY EACH YEAR. INSTRUMENTAL AND HISTORICAL DATA INDICATED THAT THE HYPOCENTER REGION OF THE RECENT EARTHQUAKE IN PAKISTAN DID NOT SHOW SIGNIFICANT SEISMIC ACTIVITY DURING THE PAST 100 YEARS AND DESCRIBE A KIND OF SEISMIC GAP. IN OTHER WORDS THE RECENT EARTHQUAKE IS THE LARGEST ONE EVER ACCURED DURING THE PAST 100 YEARS. THE RECENT EARTHQUAKE IS VERY SIMILAR TO THE 1978 TABAS EARTHQUAKE IN IRAN. THE SOURCE MECHANISM OF BOTH EARTHQUAKES HAD TRUST TYPE MECHANISMS AND BOTH HAD SHALLOW DEPTHS AND HAD VERY SIMILAR STRESS DROP. BOTH EARTHQUAKES FALLOW MANY STRONG TRUST TYPE AFTERSHOCKS.

THE CRUSTAL STRUCTURE BENEATH THREE SEISMIC STATIONS, DEPLOYED IN TEMPORARY KOPET-DAGH (KD) SEISMIC NETWORK, IN NORTH EASTERN OF IRAN IS DETERMINED USING RECEIVER FUNCTIONS ANALYSIS. IN THIS STUDY, 40 TELESEISMIC EARTHQUAKES THAT WERE RECORDED AT THE STATIONS OF KD NETWORK WERE USED TO CALCULATE RECEIVER FUNCTIONS. BY COMBINING THE RADIAL COMPONENT OF TELESEISMIC P WAVES WITH THE VERTICAL COMPONENT, IT IS POSSIBLE TO IDENTIFY S PHASE WITHIN THE P WAVEFORM. THESE PHASES ARE GENERATED BY THE MECHANISM OF P TO S CONVERSION AT DISCONTINUITIES IN VELOCITY UNDER THE RECEIVING STATION. CRUSTAL STRUCTURE MODELS CAN BE TESTED BY RECEIVER FUNCTIONS GENERATED OF SYNTHETIC SEISMOGRAMS AND COMPARING WITH THE OBSERVED DATA. A COMPLICATED CRUSTAL STRUCTURE IS SUGGESTED FOR THE BINALUD, WITH A MOHO DEPTH OF 52±1 KM THE RESULTS ARE PRESENTING THE THREE MAIN LAYERS: THE UPPER CRUST HAS A S WAVE VELOCITY BETWEEN 2.6–3.6 KM/S AND A 13±1 KM THICKNESS. THE MIDDLE CRUST HAS S WAVE VELOCITY BETWEEN 3.2– 3.9 KM/S AND A 21±1 KM THICKNESS. THE LOWER CRUST HAS S WAVE VELOCITY BETWEEN 3.6 – 4.6 KM/S AND A 18±1KM THICKNESS. THE UPPER CRUST IS DIVIDED TO TWO PARTS. TOP LAYER HAS A POSITIVE SHEAR WAVE VELOCITY GRADIENT FROM 2.6- 3.6 KM/S FROM SURFACE TO A DEPTH OF 7±1 AND BOTTOM LAYER HAS A NEGATIVE SHEAR WAVE VELOCITY GRADIENT FROM 3.6- 3.2 KM/S AND 5KM THICKNESS. THE MIDDLE CRUST ALSO IS DIVIDED TO TWO PARTS. TOP LAYER OF MIDDLE CRUST HAS 9±1 KM THICKNESS AND A 3.2-3.3 KM/S SHEAR WAVE VELOCITY. BOTTOM LAYER OF MIDDLE CRUST HAS 12±1 KM THICKNESS AND 3.4-3.9 KM/S SHEAR WAVE VELOCITY. A S WAVE VELOCITY BETWEEN 4.6– 4.7 KM/S INDICATES THE LOWER CRUST WITH MOHO AT 52±1 KM.

SPECTRAL DECOMPOSITION IS AN IMPORTANT SIGNAL ANALYSIS TOOL FOR SEISMIC DATA. TRADITIONALLY, 2D REPRESENTATION IN TIME AND FREQUENCY SPACE FOR A 1D SIGNAL IS ACHIEVED BY TAKING THE FOURIER TRANSFORM OVER A SHORT-TIME WINDOW. THE WINDOWING PROBLEM IN TIME-FREQUENCY ANALYSIS IS ABSENT IN CONTINUOUS WAVELET TRANSFORM (CWT) METHOD. TIME-FREQUENCY SPECTRA ARE OFTEN CHARACTERIZED BY AVERAGE MEASURES. THESE AVERAGE MEASURES NAMELY CENTER FREQUENCY, DOMINANT FREQUENCY AND SPECTRAL BANDWIDTH ARE COMMONLY KNOWN AS SPECTRAL ATTRIBUTES. NEWLY DEVELOPED SPECTRAL ATTRIBUTES BASED ON TIME-FREQUENCY MAP OF CONTINUOUS WAVELET TRANSFORM ARE DEVELOPED IN THIS WORK.

INVERSE MODELING OF GEOELECTRICAL DATA IS AN IMPORTANT METHOD EXPLORATION AND UNDERGROUND WATER STUDIES. INTRINSIC NONLINEAR NATURE OF GEOPHYSICAL DATA IS OBSTACLE IN MODELING PROCEDURE. HERE WE DESCRIBE A STUDY OF THE APPLICABILITY OF NEURAL NETWORKS TO SOLVING SOME GEOPHYSICAL INVERSE PROBLEMS. IN PARTICULAR, WE STUDY THE PROBLEM OF OBTAINING FORMATION RESISTIVITIES AND LAYER THICKNESSES FROM VERTICAL ELECTRICAL SOUNDING (VES) DATA.

IRAN IS A PART OF THE LARGEST CONVERGENCY REGION IN THE EARTH. IT IS CAUSED BY 3000000 KM2 WIDTH´S COVERGENC OF CONTINENTAL CURST THAT WAS CREATED BY EXPLOSION OF DEAD SEA AND MOVING ARABIAN PLATE TO THE NORTH SIDE AND THEN CONTACTS TO ORAZIA PLATE. IN THE OTHERHAND, INDIA PLATE MOVES TO THE NORTH-NORTH-WEST AND IT CLOSES TO IRAN PLATE. RESULTS THEM IS TURNING OF IRAN PLATE AROUND ORAZIA. (JACKSON AT ALL1990).EARTHQUAKE IS THE MOST IMPORTANT EVENT IN THIS CONVERGENCY. CONSIDERING OF EARTHQUAKES AND THEIR RELATION TO SEISM TECTONIC IN A REGION, CAN BE USEFUL FOR REALIZING HOW HAPPEN EARTHQUAKES IN THE DIFFERENT REGION. UNDERSTAND OF SEISMICITY POWER AND EARTHQUAKE PARAMETERS MAKE IMPROVE SEISMIC DESING OF STRUCTURE.IN THIS ESSAY WE TRIED TO SURYEY, TECTONIC AND SEISM TECTONIC IN THE NORTH- WEST OF IRAN. AFTER THAT WE WILL INTRODUCE SEISMIC SOURSES AND SEISMIC PARAMETERS IN THIS REGION .THE LEAST AND THE MOST DANGEROUS PARTS OF THIS REGION WILL INTRODUCE YOU.

GEOMAGNETIC FIELD VARIES WITH TIME AND POSITION IN A COMPLICATED WAY. A TYPE OF MICROPULSATION AS A TRANSIENT VARIATION HAS RECORDED DURING EARTHQUAKE OCCURRENCE. ACCORDING TO THE OCCURRENCE OF EARTHQUAKES AND EARTHQUAKE PARAMETERS SUCH AS MAGNITUDE, FOCAL DEPTH AND DISTANCE BETWEEN EPICENTER AND MAGNETIC OBSERVATORY, THE ORIGIN OF THIS TYPE OF PULSATION CAN BE GUESSED. MICRO FRACTURING ELECTRIFICATION AND ALONG WITH ULF ELECTROMAGNETIC EMISSION IN EARTHQUAKE ZONE IS SUGGESTED AS A POSSIBLE MECHANISM FOR EXPLAINING MICROPULSATION. SO THE NEW TYPE OF MICRO PULSATION WITH FREQUENCY RANG BETWEEN 0.1 HZ TO 1HZ IS INTRODUCED.

WE AIM TO ESTIMATE THE DEPTH OF SUBSURFACE CAVITIES FROM MICROGRAVITY DATA THROUGH A MULTI-LAYER PERCEPTRON (MLP) NEURAL NETWORK. INFACT, THIS METHOD IS AN INTELLIGENT WAY TO INTERPRET MICROGRAVITY DATA AND GAIN AN ESTIMATION OF DEPTH. THE MLP NEURAL NETWORK WAS TRAINED FOR TWO MAIN MODELS OF CAVITIES: SPHERE AND CYLINDER IN A DOMAIN OF RADIUS AND DEPTH. WE TESTED DIFFERENT MLP’S WITH DIFFERENT NUMBER OF NEURONS IN THE HIDDEN LAYER AND OBTAINED THE OPTIMUM VALUE FOR NUMBER OF NEURONS IN THE HIDDEN LAYER. THEN IT WAS TESTED IN PRESENT OF 30% NOISE (S/N=.3), AND ALSO TESTED FOR REAL DATA. IT PRESENTED GOOD RESULTS FOR DEPTH ESTIMATION OF SUBSURFACE CAVITIES.

IN THIS PAPER, AT FIRST WE SAY ABOUT THE AVO THEORY. A SEISMIC LINE FROM ONE OIL FIELD AT PERSIAN GOLF AND TWO WELLS ARE SELECTED TO INDICATE THE RESULTS OF APPLICATION OF AVO ANALYSIS FOR DETECTION OF HYDROCARBON RESERVOIR IN THIS FIELD.A SPECIAL AVO PROCESSING WAS APPLIED TO DATA USING VISTA PACKAGE SOFTWARE. TO OBTAIN BROADBAND DATA AND SUPPRESSION OF NOISE AND MULTIPLES, DECONVOLUTION AND RADON TRANSFORM WERE PERFORMED. IN AVO INTERPRETATION AN AMPLITUDE ANOMALY IN AVO ATTRIBUTES WAS DETECTED. THEN A CDP GATHER WAS CHECKED FOR OUR HYPOTHESIS. IN THE NEXT STAGE AN ITERATIVE AND LINEARZED INVERSION ALGORITHM CARRIED OUT IN THE X-T DOMAIN HAS BEEN APPLIED TO A CDP GATHER .THEN WELL LOGS ARE USED TO GENERATE THE INITIAL STARTING MODEL FOR THE INVERSION. THE INVERSION, PERFORMED WITH STARTING MODEL IN PAY ZONES HAVING A POISSON’S RATIO APPROPRIATE WITH HYDROCARBON SATURATION IN THE TARGET ZONE, THERE IS CONVERGENCE FROM THE INITIAL TO THE REAL SEISMIC GATHER.AT LAST STAGE, IT WAS COMPUTED P-WAVE VELOCITY MAP OF SECTION BY FINDING A MULTI-LINEAR RELATIONSHIP BETWEEN SONIC LOGS AND ATTRIBUTES. THEN THIS RELATIONSHIP WAS APPLIED TO THE ATTRIBUTES. AT THE P-WAVE VELOCITY COMPUTED SECTION FOUND A LOW VELOCITY ANOMALY THAT MATCHED WITH AVO ANOMALY IN OTHER ATTRIBUTES.THESE PROVED THAT THE OBSERVED AVO ANOMALY IS GAS CAP OF THE FIELD.