Introduction to the use of gravity measurements
|
|
- Bertram Davidson
- 6 years ago
- Views:
Transcription
1 Introduction to the use of gravity measurements Background & basic intuition Data reduction Use of the instrument See Reynolds, Chpt 2, for detailed quantitative discussion
2 What and Why Gravity measures the distribution of mass Variations in density Variations in interface locations Very non-unique => use in conjunction with other constraints (geologic, seismic, magnetic ) Targets include: Topographic compensation - the crustal root (long λ) Fault structures/offsets (best for dip-slip faults or large offset strike-slip) Basin sediment fill depth (together with magnetic field variations) Aquifers Tunnels Buried bodies (tunnels, ore deposits, )
3 Data Availability Global: Satellite tracking/altimetry (over water)/other ~2 km resolution over oceans ~100 km resolution from harmonic models None of these useful for our purposes Regional: Carry the gravimeter around Land, boat, plane Arbitrary resolution
4 Basic intuition Everything we need can be worked out from basic potential field theory (see Reynolds or Turcotte & Schubert): 2 V = 0 where V is the gravitational potential g z = V z where g z is the vertical component of the gravity field Units: 1 mgal = 10-5 m/s 2 1 g.u. = 0.1 mgal = 10-6 m/s 2
5 Attraction from harmonic distribution of mass I Z Δρh k cos( kx) = Δσ k cos( kx) Why? Intuition Decompose any mass distribution into individual harmonic (Fourier) contributions and sum linearly Example: Topography, density variations on a 2D or 3D grid X!
6 Attraction from harmonic distribution of mass II We won t derive solutions today, but you can imagine integrating δg = Gδm r 2 over our given harmonic mass distribution. The vertical component is: where k = 2π/λ, h<<λ ˆ r g z = 2πGΔρh k cos( kx)e kz = 2πGΔσ k cos( kx)e kz The e -kz term corresponds to the 1/r 2 decay with distance (the peaks and troughs tend to cancel when viewed from increasingly large distances) Z Δρh k cos( kx) = Δσ k cos( kx) X!
7 Attraction from harmonic distribution of mass III At long λ, k 0 g z = 2πGΔρh = 2πGΔσ No z-dependence Attraction from an infinite sheet of mass Will be used in making the Bouguer correction For z 0 If z increases (or k increases λ decreases): e -kz 0 Upward continuation: e.g., ΔZ=λ, e -2π =0.002 (faint signals) Downward continuation: e.g., ΔZ=-λ, e 2π =500 (amplification of short λ noise)
8 Measurements Absolute Needs known reference station to tie to Relative Small scales are fast (what we typically do) Common corrections before getting to interesting signal 1. Instrument drift: return to base station regularly 2. Tides: return to base station regularly 3. Latitude (proximity to Earth center, change in mass on ellipsoid, rotation) 88.9 mgal / degree latitude (we typically wont deal with this for our small surveys) 4. Free Air 5. Bouguer
9 Free Air Correction Bring all observations to a common horizontal reference surface (E.g., a datum or geoid) Effect of distance not mass Results in Free Air Gravity Commonly used for airborne and marine data g 0 = Gm R 2 ; g h = Gm (R + h) 2 δg FA h = g h g 0 h 2g 0 R The L&R gravimeter has a sensitivity of ~3µGal h = δg R FA 1cm 2g 0 Careful with surveying (know your target) = mgals/m
10 Bouguer Correction Effect of mass (not distance) - Assume λ>>h, ignores dh/dx + g B = 2πGΔρh Δρ h h x What density to use? Standard is 2670 kg/m 3 You can also use this to estimate density (scramble the above) Nettleton s Approach - assume all variations are due to topography Clever differencing of gravity profiles is sometimes useful More sophisticated approaches Terrain corrections (graphical) Talwani (2D and 2.5D prisms - Matlab) Parker s Method (finite amplitude harmonic summation) Common Shapes: (Burger et al., Sec. 6.5) Vert/Horiz sheet/cylinder, quarter sheets, spheres, polygons
11 The Locoste & Romberg Model G Gravimeter Love and Care $$,$$$ Needs power to keep isothermal - keep plugged in somewhere Highly sensitive spring and mass system (read Reynolds) - Do not walk around without clamping the mass Getting data Level gravimeter (you want all of g z ) Unclamp Get a reading by adjusting the spring s.t. mass is in the right place - can be tedious if you have changed location a lot A manual raw data point is derived by reading off the counts and converting to mgals using a calibrated table (or Matlab) or use the feedback system to record relative values in mgals Reclamp Return to base station every ~30 minutes for tide/drift correction.
12 Homework 1) Considering the free air anomaly expression, use gravity to estimate the height of each floor of Milliken (use the stairwell). Make sure to correct for any tidal/drift effects by interpolating differences in the base station measurement at the beginning and end of the survey. Make sure to note the time. Take care to clamp the mass. 2) Given the coordinates of Caltech (34:09N, 118:10W, 250 m.a.s.l.) and our field area, and assuming all other factors are constant, which area do you expect will have a higher vertical component of the gravity field? (Hint: compare effects of latitude correction vs. FA correction.)
r 1 r 2 r 3 Dr is what matters!
Today s Agenda Gravity - Background & basic intuition - Data reduction - Use of the instrument - See textbook for detailed quantitative discussion - Measure height of Millikan or S. Mudd What and Why Gravity
More informationIntroduction to the use of gravity measurements in Ge111A
Introduction to the use of gravity measurements in Ge111A Background & basic intuition Data reduction Use of the instrument See Reynolds for detailed quantitative discussion What and Why Gravity measures
More informationGravity data reduction
Gravity data reduction REDUCTION: raw data à gravity anomaly data Temporal corrections tides and instrument drift Spatial corrections latitude and elevation GRS67 = gravity variation with latitude at sea
More informationhttp://foundation.aapg.org/students/undergraduate/weeks.cfm Tim Carr - West Virginia University 3 Potential Fields Indirect Visualization Density and Magnetization Gravity and Magnetic Exploration Locate
More information2.2 Gravity surveys. Gravity survey
2.2 Gravity surveys Gravity survey The effect of latitude The effect of elevation The Bouguer effect Topographic effect The effect of tides Summary of corrections Gravity in boreholes Gravity survey In
More informationmdu G = Fdr = mgdr Dr. Clint Conrad POST 804 Gravity, the Geoid, and Mantle Dynamics Lecture: Gravity and the Geoid U G = G M r
GG 611 Big Gulp Fall 2014 Gravity, the Geoid, and Mantle Dynamics Lecture: Gravity and the Geoid Dr. Clint Conrad POST 804 clintc@hawaii.edu Gravitational Potential For a point mass: Newton s law of gravitation:
More informationLab 8: Gravity and Isostasy (35 points)
it's not the most important thing in your life right now. But what is important is gravity. Arnold Schwarzenegger as Colonel John Matrix, Commando (Check out this classic of American cinema!) Lab 8: Gravity
More informationGRAVITY EXPLORATION (Gph 301) Chokri Jallouli 2014/2015
KING SAUD UNIVERSITY FACULTY OF SCIENCES Department of Geology and Geophysics GRAVITY EXPLORATION (Gph 301) Chokri Jallouli 2014/2015 INTRODUCTION Definition Gravity method consists of measuring, studying
More informationGRAVITY EXPLORATION. subsurface density. (material property) Gravity anomalies of some simple shapes
GRAVITY EXPLORATION g at surface (observation) subsurface density (material property) subsurface geology Gravity anomalies of some simple shapes Reminder: we are working with values about... 0.01-0.001
More informationTotal gravitational field is sum of contributions from all masses.
Gravity force (acceleration) vs potential (energy) acceleration (g) => GM/r 2 Potential => - GM/r G is Newton s gravitational constant 6.67x10-11 (S.I. units) you should determine what the S.I. units are
More informationLast week we obtained a general solution: 1 cos αdv
GRAVITY II Surface Gravity Anomalies Due to Buried Bodies Simple analytical solution may be derived for bodies with uniform density contrast simple shape, such as: Sphere Horizontal/vertical cylinders
More informationNote that gravity exploration is different to seismic exploration in the following way:
224B3 Other factors that cause changes in g and need to be corrected Note that gravity exploration is different to seismic exploration in the following way: In a seismic survey, the travel time depends
More informationDetermination of Subsurface Bulk Density Distribution for Geotechnical Investigation using Gravity Technique
Journal of Earth Sciences and Geotechnical Engineering, vol. 7, no.2, 2017, 63-69 ISSN: 1792-9040 (print), 1792-9660 (online) Scienpress Ltd, 2017 Determination of Subsurface Bulk Density Distribution
More informationOUTLINE. Many of us secretly dream of six months without gravity COURSE DESCRIPTION
GEOL 481.3 OUTLINE POTENTIAL FIELD METHODS GEOL 481.3 email: jim.merriam@usask.ca POTENTIAL FIELD METHODS Many of us secretly dream of six months without gravity Allan Fotheringham COURSE DESCRIPTION This
More informationGravity Methods (IV)
Environmental and Exploration Geophysics II Gravity Methods (IV) tom.h.wilson tom.wilson@mail.wvu.edu Department of Geology and Geography West Virginia University Morgantown, WV Possible employment opportunities
More informationCHAPTER X. Second Half Review 2017
CHAPTER X Second Half Review 217 Here is a quick overview of what we covered in the second half of the class. Remember that the final covers the whole course but there will naturally be a bias towards
More informationINTRODUCTION TO APPLIED GEOPHYSICS
INTRODUCTION TO APPLIED GEOPHYSICS EXPLORING THE SHALL0W SUBSURFACE H. Robert Burger Anne F. Sheehan Craig H.Jones VERSITY OF COLORADO VERSITY OF COLORADO W. W. NORTON & COMPANY NEW YORK LONDON Contents
More informationHOMEWORK 3 Draft presentations due November 4 Oral presentations of Group problems, November 6, November 8
HOMEWORK 3 Draft presentations due November 4 Oral presentations of Group problems, November 6, November 8 Group A1 Modeling marine magnetic anomalies Write a Matlab program to generate marine magnetic
More informationMagnetic and Gravity Methods for Geothermal Exploration
Magnetic and Gravity Methods for Geothermal Exploration Dr. Hendra Grandis Geophysics - ITB method and survey procedure Aero- or ground magnetic (covers a large area) Schlumberger resistivity mapping and
More informationGetting Started: Using and Understanding Gravity Data
The University of Texas at El Paso Pan-American Center for Earth and Environmental Studies Thu 13-Sep-2007 ABOUT PACES Mission Newsletter Sponsors RESEARCH Geoinformatics Remote Sensing Geoscience GIS
More informationGeothermal Energy Resources Exploration using Gravity and magnetics. By Mariita, N.O. KenGen
Geothermal Energy Resources Exploration using Gravity and magnetics By Mariita, N.O. KenGen What is Geothermal Energy? Geothermal Energy = heat from the Earth Transmitted by fluids via fractures and pores
More informationHIMALAYAN AIRBORNE GRAVITY AND GEOID OF NEPAL
Mt. Everest HIMALAYAN AIRBORNE GRAVITY AND GEOID OF NEPAL -Niraj Manandhar Head, Geodetic Survey Branch Survey Department, Geodetic Survey Branch Project Background Air Borne Gravity Survey Project was
More information3. Magnetic Methods / 62
Contents Preface to the Second Edition / xv Excerpts from Preface to the FirstEdition / xvii Mathematical Conventions / xix 1. Introduction / 1 Reference / 5 2. Gravity Methods / 6 2. I. Introduction /
More informationIterative 3D gravity inversion with integration of seismologic data
BOLLETTINO DI GEOFISICA TEORICA ED APPLICATA VOL. 40, N. 3-4, pp. 469-475; SEP.-DEC. 1999 Iterative 3D gravity inversion with integration of seismologic data C. BRAITENBERG and M. ZADRO Department of Earth
More informationEnvironmental and Exploration Geophysics I Gravity I tom.h.wilson
Environmental and Exploration Geophysics I Gravity I tom.h.wilson tom.wilson@mail.wvu.edu Department of Geology and Geography West Virginia University Morgantown, WV Discuss mid term exam Objectives for
More informationPART A: Short-answer questions (50%; each worth 2%)
PART A: Short-answer questions (50%; each worth 2%) Your answers should be brief (just a few words) and may be written on these pages if you wish. Remember to hand these pages in with your other exam pages!
More informationENVI.2030L - Plate Tectonics - Geomagnetism, Earthquakes, and Gravity
I. Geomagnetism Name ENVI.2030L - Plate Tectonics - Geomagnetism, Earthquakes, and Gravity The earth's magnetic field can be viewed as a simple bar magnet located near the center of the earth and inclined
More information5. Gravity. 5.1 Geoid Variations. The Australian Continent: A Geophysical Synthesis Gravity
34 The Australian Continent: A Geophysical Synthesis Gravity 5. Gravity Gravity data map subtle changes in the Earth s gravitational field caused by variations in the density of the underlying materials.
More informationCENTIMETRE LEVEL OF ACCURACY OF QUASIGEOID MODEL IN POLAND
CENTIMETRE LEVEL OF ACCURACY OF QUASIGEOID MODEL IN POLAND Jan Krynski Institute of Geodesy and Cartography, Poland krynski@igik.edu.pl Adam Lyszkowicz University of Warmia and Mazury in Olsztyn, Poland
More informationGravitational constraints
Gravitational constraints Reading: Fowler p172 187 Gravity anomalies Free-air anomaly: g F = g g( λ ) + δg obs F Corrected for expected variations due to the spheroid elevation above the spheroid Bouguer
More informationGRAVITY AND MAGNETIC SURVEY NECHAKO BASIN STUDY ACQUISITION AND PROCESSING PHASE
GRAVITY AND MAGNETIC SURVEY NECHAKO BASIN STUDY ACQUISITION AND PROCESSING PHASE Report prepared for the B.C. Ministry of Energy and Mines Resource Development Division New Ventures Branch by Bemex Consulting
More informationGEOID UNDULATIONS OF SUDAN USING ORTHOMETRIC HEIGHTS COMPARED WITH THE EGM96 ANG EGM2008
GEOID UNDULATIONS OF SUDAN USING ORTHOMETRIC HEIGHTS COMPARED Dr. Abdelrahim Elgizouli Mohamed Ahmed* WITH THE EGM96 ANG EGM2008 Abstract: Positioning by satellite system determine the normal height above
More informationHeight systems. Rudi Gens Alaska Satellite Facility
Rudi Gens Alaska Satellite Facility Outline Why bother about height systems? Relevant terms Coordinate systems Reference surfaces Geopotential number 2 Why bother about height systems? give a meaning to
More informationLast Time. Today s s Agenda. Geophysics. Geophysics. Geophysics. MAS 603: Geological Oceanography. Lecture 21: Geophysics 1: Gravity
UNIVERSITY OF SOUTH ALABAMA Last Time MAS 603: Geological Oceanography Extinctions Lecture 21: 1: http://www.cartoonstock.com/newscartoons/cartoonists/for/lowres/forn441l.jpg Today s s Agenda Introduction
More informationDisplacement at very low frequencies produces very low accelerations since:
SEISMOLOGY The ability to do earthquake location and calculate magnitude immediately brings us into two basic requirement of instrumentation: Keeping accurate time and determining the frequency dependent
More informationGRAVIMETRIC MAP OF CHILE. Services Mining and Engineering Geophysics Instituto Geográfico Militar
GRAVIMETRIC MAP OF CHILE Araneda M., Rivas L., Avendaño M, Sottolichio G., Rubio W. Services Mining and Engineering Geophysics segmi@netexpress.cl) Instituto Geográfico Militar (lrivas@igm.cl) Abstract
More informationTERRAIN (BOUGUER) DENSITY. One of the largest effects on gravity is the attraction of the topography near the
TERRAIN (BOUGUER) DENSITY One of the largest effects on gravity is the attraction of the topography near the gravity station. This is distinct from the Bouguer correction, which corrects for the attraction
More information(b) What is the amplitude at the altitude of a satellite of 400 km?
Practice final quiz 2015 Geodynamics 2015 1 a) Complete the following table. parameter symbol units temperature T C or K thermal conductivity heat capacity density coefficient of thermal expansion volumetric)
More informationIntroduction. Matlab output for Problems 1 2. SOLUTIONS (Carl Tape) Ge111, Assignment #3: Gravity April 25, 2006
SOLUTIONS (Carl Tape) Ge111, Assignment #3: Gravity April 25, 26 Introduction The point of this solution set is merely to plot the gravity data and show the basic computations. This document contains a
More informationSURVEI GRAVITI (Gravity Surveying)
Introduction SURVEI GRAVITI (Gravity Surveying) Gravity surveys measure the acceleration due to gravity, g. Average value of g at Earth s surface is 9.80 ms -2. Gravitational attraction depends on density
More informationGravity Methods (VII) more wrap up
Environmental and Exploration Geophysics II Gravity Methods (VII) more wrap up tom.h.wilson tom.wilson@mail.wvu.edu Department of Geology and Geography West Virginia University Morgantown, WV 0.4 0.35
More informationHeight systems. Rüdiger Gens
Rüdiger Gens 2 Outline! Why bother about height systems?! Relevant terms! Coordinate systems! Reference surfaces! Geopotential number! Why bother about height systems?! give a meaning to a value defined
More information9. Density Structure. The Australian Continent: A Geophysical Synthesis Density Structure
84 The Australian Continent: A Geophysical Synthesis Density Structure 9. Density Structure Although the primary focus for the development of the AuSREM model was the creation of 3-D seismic wavespeed
More informationGeophysics for Environmental and Geotechnical Applications
Geophysics for Environmental and Geotechnical Applications Dr. Katherine Grote University of Wisconsin Eau Claire Why Use Geophysics? Improve the quality of site characterization (higher resolution and
More informationThe anomalous high transverse ridge developed along a transform fault. Speaker: Yen-Fu Chen
The anomalous high transverse ridge developed along a transform fault Speaker: Yen-Fu Chen Reference Anne E. Deschamps, Serge E. Lallemand, and Jean-Yves Collot, 1998, A detailed study of the Gagua Ridge:
More information10 Least-squares collocation
10 Least-squares collocation 10.1 Principles of least-squares collocation The principle of collocation is very simple. The anomalous potential T outside the earth is a harmonic function, that is, it satisfies
More informationGRAVITY AND MAGNETIC METHODS
Presented at Short Course IX on Exploration for Geothermal Resources, organized by UNU-GTP, GDC and KenGen, at Lake Bogoria and Lake Naivasha, Kenya, Nov. 2-24, 2014. Kenya Electricity Generating Co.,
More informationGPS Measurement Protocol
GPS Measurement Protocol Purpose To determine the latitude, longitude, and elevation of your school and of all your GLOBE sites Overview The GPS receiver will be used to determine the latitude, longitude
More informationPGM2016: A new geoid model for the. Philippines
PGM2016: A new geoid model for the Philippines United Nations/Nepal Workshop on the Applications of Global Navigation Satellite Systems Kathmandu, Nepal December 12-16, 2016 Ronaldo Gatchalian, Chief Geodesy
More informationTidal Effects on Earth s Surface
Tidal Effects on Earth s Surface Tom Murphy February, 1 This treatment follows the conventions of F. D. Stacey s Physics of the Earth, and is largely an elaboration on this work. 1 Tidal Potential The
More informationSection 2: Gravity Surveying
Introduction Section 2: Gravity Surveying Gravity surveys measure the acceleration due to gravity, g. Average value of g at Earth s surface is 9.80 ms -2. Gravitational attraction depends on density of
More informationThe GOCE Geoid in Support to Sea Level Analysis
The GOCE Geoid in Support to Sea Level Analysis The geoid is a very useful quantity for oceanographers Thomas Gruber Astronomical & Physical Geodesy (IAPG) Technische Universität München 1. Characteristics
More informationGeophysics Departmental Exam: 2004 Part 1
2004 Geophysics Departmental Exam: 2004 Part 1 This section is 90 minutes, closed book, and consists of questions designed to test your knowledge of facts and figures in the geosciences. The focus will
More informationDepartment of Geophysics Faculty of Earth Sciences King Abdulaziz University
Department of Geophysics Faculty of Earth Sciences King Abdulaziz University Dr. Mansour A. Al-Garni Office: room 233/Buld. 27 OR Dept. chair office/buld. 55 Introduction to Geophysics EGP 211 Time: 10-10:55
More informationIsostacy: Compensation of Topography and Isostatic Geoid Anomalies
Isostacy: Compensation of Topography and Isostatic Geoid Anomalies November 3, 2016 1 Isostacy One of the major goals of interpreting planetary gravity fields is to understand how topography positive (
More information(1) Identify 5 major principles of relative dating? For each principle, describe how you tell what is younger and what is older.
Things to Know - Third GLG101Exam Page 1 Important Note: This is not everything you need to know or study. However, it provides you with a relatively comprehensive list of questions to help you study.
More informationSummary so far. Geological structures Earthquakes and their mechanisms Continuous versus block-like behavior Link with dynamics?
Summary so far Geodetic measurements velocities velocity gradient tensor (spatial derivatives of velocity) Velocity gradient tensor = strain rate (sym.) + rotation rate (antisym.) Strain rate tensor can
More informationLOCATING AND CHARACTERIZING ABANDONED MINES USING MICROGRAVITY by Richard C. Benson 1, Ronald D. Kaufmann 1, Lynn Yuhr 1, Richard Hopkins 2 ABSTRACT
LOCATING AND CHARACTERIZING ABANDONED MINES USING MICROGRAVITY by Richard C. Benson 1, Ronald D. Kaufmann 1, Lynn Yuhr 1, Richard Hopkins 2 ABSTRACT Surface geophysical methods can be an important part
More informationREGIONAL GEOPHYSICS RESEARCH GROUP. Technical Report WK/91/2. Regional Geophysics Series
British Geological Survey REGIONAL GEOPHYSICS RESEARCH GROUP Technical Report WK/91/2 Regional Geophysics Series Regional infill gravity survey in north-east Antrim, Northern Ireland J P Busby j Natural
More informationStatic Corrections for Seismic Reflection Surveys
Static Corrections for Seismic Reflection Surveys MIKE COX Volume Editors: Series Editor: Eugene F. Scherrer Roland Chen Eugene F. Scherrer Society of Exploration Geophysicists Tulsa, Oklahoma Contents
More informationGravity-Magnetic & Magneto-Telluric surveys in Purnea Onland Basin, India - A case history.
P-281 Gravity-Magnetic & Magneto-Telluric surveys in Purnea Onland Basin, India - A case history. Summary A.K. Roy, D.P. Paine*, S. Sett, and H.N. Bhattacharya, ONGC This paper describes a case history
More informationPrinciples of Applied Geophysics
Principles of Applied Geophysics Fifth edition D.S. Parasnis Professor emeritus of Applied Geophysics Department of Applied Geophysics, University ofluled, Lulea, Sweden Fellow of the Royal Swedish Academy
More informationFigure 1 Answer: = m
Q1. Figure 1 shows a solid cylindrical steel rod of length =.0 m and diameter D =.0 cm. What will be increase in its length when m = 80 kg block is attached to its bottom end? (Young's modulus of steel
More informationCase study of Japan: Reference Frames in Practice
Case study of Japan: Reference Frames in Practice Basara Miyahara and Koji Matsuo Sponsors: 1 Outline Introduction - Geodetic reference frame of Japan - GEONET : continuous GNSS observation system Geometric
More informationFinal Project Teaching Quantitative Skills in Geoscience Context Carleton College: July 24 July 27, 2002
Final Project Teaching Quantitative Skills in Geoscience Context Carleton College: July 24 July 27, 2002 Albert T. Hsui, University of Illinois at Urbana-Champaign Ping Wang, University of South Florida
More informationD DAVID PUBLISHING. Towards a New Geoid Model of Tanzania Using Precise Gravity Data. 1. Introduction. Selassie David Mayunga
Journal of Environmental Science and Engineering A 5 (2016) 267-276 doi:10.17265/2162-5298/2016.05.005 D DAVID PUBLISHING Towards a New Geoid Model of Tanzania Using Precise Gravity Data Selassie David
More information12 Gravity and Topography
12. Gravity and Topography 126 12 Gravity and Topography In the limit of perfect hydrostatic equilibrium, there is an exact relationship between gravity and topography... and no new information emerges:
More informationPhysics and Chemistry of the Earth and Terrestrial Planets
MIT OpenCourseWare http://ocw.mit.edu 12.002 Physics and Chemistry of the Earth and Terrestrial Planets Fall 2008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.
More informationGravity Monitoring with a Superconducting Gravimeter in Vienna
1 of 10 2/18/2011 3:30 PM Gravity Monitoring with a Superconducting Gravimeter in Vienna Bruno Meurers Institute of Meteorology and Geophysics, University of Vienna Central Institute of Meteorology and
More information5 GRAVITATION Last Updated: July 16, 2012
Problem List 5.1 Total mass of a shell 5.2 Tunnel through the moon 5.3 Gravitational field above the center of a thin hoop 5.4 Gravitational force near a metal-cored planet surrounded by a gaseous cloud
More informationESA training. Gravity, magnetics and gradients for mapping and modelling. Jörg Ebbing. Department of Geosciences Kiel University
ESA training Gravity, magnetics and gradients for mapping and modelling Jörg Ebbing Department of Geosciences Kiel University Contributions from: Eldar Baykiev (Trondheim), Des Fitzgerald (Melbourne),
More informationC3: Magnetic anomalies produced by simple geological structures. Remember that objects can acquire both induced and remnant magnetization.
Geophysics 3 February 009 C3: Magnetic anomalies produced by simple geological structures Remember that objects can acquire both induced and remnant magnetization. Induced magnetization will disappear
More informationCo-seismic Gravity Changes Computed for a Spherical Earth Model Applicable to GRACE Data
Chapter 2 Co-seismic Gravity Changes Computed for a Spherical Earth Model Applicable to GRACE Data W.Sun,G.Fu,andSh.Okubo Abstract Dislocation theories were developed conventionally for a deformed earth
More informationDevelopment of a Borehole Gravity Meter for Mining Applications
Ground and Borehole Geophysical Methods Paper 111 Development of a Borehole Gravity Meter for Mining Applications Seigel, H. O. [1], Nind, C. [1], Lachapelle, R. [1], Chouteau, M. [2], Giroux, B. [2] 1.
More informationPrecise Hong Kong Geoid HKGEOID-2000
Yong-Qi Chen 1, Zhicai Luo 1 and Simon Kwok 2 1.Department of Land Surveying and Geo-Informatics, The Hong Kong olytechnic University 2 Geodetic Survey Section, Lands Department, HKSAR Abstract: This paper
More informationC5 Magnetic exploration methods data analysis techniques
C5 Magnetic exploration methods data analysis techniques C5.1 Data processing and corrections After magnetic field data have been collected a number of corrections are applied to simplify the interpretation.
More informationCHAPTER FOUR GEOPHYSICAL INTERPRETATION AND DISCUSSION
CHAPTER FOUR GEOPHYSICAL INTERPRETATION AND DISCUSSION 4.1. DATA PROCESSING AND INTERPRETATION 4.1.1. Introduction Processing of potential field data entails the application of various filters to the data
More informationThe earth s gravitational field
The earth s gravitational field T. Ramprasad National Institute of Oceanography, Dona Paula, Goa-403 004 rprasad@nio.org Gravity Gravity is a force that for us is always directed downwards. But to say
More informationGeologic Mapping Invitational Trial Event
Geologic Mapping Invitational Trial Event A TEAM OF UP TO: 2 Team Name AVAILABLE TIME: 50 min Required Materials: Each team MUST have a protractor, ruler, non-programmable calculator, colored pencils,
More information1/28/16. EGM101 Skills Toolbox. Oblate spheroid. The shape of the earth Co-ordinate systems Map projections. Geoid
EGM101 Skills Toolbox Oblate spheroid The shape of the earth Co-ordinate systems Map projections The geoid is the shape that the surface of the oceans would take under the influence of Earth's gravitation
More informationscale Three-dimensional Modelling
Lithospheric-scale scale Three-dimensional Modelling (Application to the EARS and Plateau) Girma Woldetinsae (Geological Survey of Ethiopia) and H.-J. Götze R. Hackney S. Schmidt (Institut für Geowissenschaften
More informationSUPPLEMENTARY INFORMATION
doi:10.1038/nature10566 1 Supplementary Figure 1. Map showing the location of airborne geophysical tracks and seismic stations for the Gamburtsev Subglacial Mountains and adjacent regions of East Antarctica
More informationDepth and shape solutions from residual gravity anomalies due to simple geometric structures using a statistical approach
Contributions to Geophysics and Geodesy Vol. 47/2, 2017 (113 132) Depth and shape solutions from residual gravity anomalies due to simple geometric structures using a statistical approach El-Sayed ABDELRAHMAN,
More informationThree-dimensional geophysical modelling of the Alalobeda geothermal field
Three-dimensional geophysical modelling of the Alalobeda geothermal field Daniele Rizzello 1, Egidio Armadillo 2, Claudio Pasqua 2,3, Massimo Verdoya 2, Solomon Kebede 4, Andarge Mengiste 4, Getenesh H/Giorgis
More informationPotential Field investigation of Williston Basin Basement
Potential Field investigation of Williston Basin Basement Jiakang Li* and Igor Morozov, University of Saskatchewan, Canada Summary Major faults and domains are identified in the Precambrian basement of
More informationGravity 2. Gravity 2. Maps and Profiles. Chuck Connor, Laura Connor. Potential Fields Geophysics: Week 1.5. Gravity 2
Maps and Profiles Chuck Connor, Laura Connor Potential Fields Geophysics: Week 1.5 Objectives for Week 1 Review the types of gravity maps Learn about the scale of gravity anomalies Make a gravity map Types
More informationA Mission to Planet Mars Gravity Field Determination
A Mission to Planet Mars Gravity Field Determination Department for Theoretical Geodesy Graz University of Technology and Space Research Institute Austrian Academy of Sciences Gravity field CHAMP GRACE
More information224 D4 Instrumentation and data collection techniques for magnetic exploration
224 D4 Instrumentation and data collection techniques for magnetic exploration D4.1 Instrumentation D4.1.1 Flux gate magnetometer Details of operation are described in Keary and Brooks Measures the component
More informationB6 Isostacy. B6.1 Airy and Pratt hypotheses. Geophysics 210 September 2008
B6 Isostacy B6.1 Airy and Pratt hypotheses Himalayan peaks on the Tibet-Bhutan border In the 19 th century surveyors used plumblines and theodolites to map India. A plumb line was used when measuring the
More informationIntro to magnetic methods
Environmental and Exploration Geophysics I Intro to magnetic methods tom.h.wilson tom.wilson@mail.wvu.edu Department of Geology and Geography West Virginia University Morgantown, WV Items on the list Gravity
More informationGRAVITY AND ISOSTASY
GRAVITY AND ISOSTASY Gravity The Geoid is the oblate spheroid -- the sea level surface over the entire Earth's surface Physically, the Geoid is an equipotential surface for gravity (i.e. the surface for
More informationENV-5004B/ENVK5005B. Figure 6. Student Registration No. ENV-5004B/ENVK5005B Version 2
ENV-5004B/ENVK5005B Figure 6 Student Registration No UNIVERSITY OF EAST ANGLIA School of Environmental Sciences Main Series UG Examination 014-15 SOLID EARTH GEOPHYSICS SOLID EARTH GEOPHYSICS WITH FIELDCOURSE
More informationGOCE-GDC: Towards a better understanding of the Earth s interior and geophysical exploration research Work Package 5 - Geophysics B
GOCE-GDC: Towards a better understanding of the Earth s interior and geophysical exploration research Work Package 5 - Geophysics B Zdeněk Martinec Dublin Institute for Advanced Studies 5 Merrion Square,
More informationGravimetric Tide observation at Lake Nasser Region, Aswan, Egypt
Gravimetric Tide observation at Lake Nasser Region, Aswan, Egypt R.M. Hassan, E.M. Abdelrahman, A. Tealeb, K.H. Zahran and G. Jentzsch ABSTRACT The LaCoste and Romberg gravimeter D-218 of the National
More informationLecture 2: Gravity, Isostasy and Flexure
Lecture 2: Gravity, Isostasy and Flexure Read pages 42-51 in KK&V You can access all of KK&V through ereserves (password: yf160) Homework 1 is due next Thursday Gravity: theory and measurements Newton:
More informationBlind fault Configuration in Osaka, Japan based on 2D gravity inversion
Blind fault Configuration in Osaka, Japan based on 2D gravity inversion N. Inoue & N. Kitada Geo-research Institute, Osaka, Japan K. Takemura Institute for Geothermal Sciences, Kyoto University, Beppu,
More informationTo the best of our knowledge, the FG5 gravimeter represents the current state-of-the-art in the measurement of absolute gravity.
FG5 gravity meter To the best of our knowledge, the FG5 gravimeter represents the current state-of-the-art in the measurement of absolute gravity. American Geophysical Union, EOS Journal Since its introduction
More informationGRAVITY SURVEY TEELS MARSH PROSPECT
GRAVITY SURVEY over the TEELS MARSH PROSPECT MINERAL COUNTY, NV for Dajin Resources (US) Corp. March 2015 SUBMITTED BY Magee Geophysical Services LLC 465 Leventina Canyon Road Reno, Nevada 89523 USA TEL
More informationMAE106 Laboratory Exercises Lab # 6 - Vibrating systems
MAE106 Laboratory Exercises Lab # 6 - Vibrating systems Goals Understand how the oscillations in a mechanical system affect its behavior. Parts & equipment Qty Part/Equipment 1 Seeeduino board 1 Motor
More informationGeologic Mapping Regional Tournament Trial Event
Geologic Mapping Regional Tournament Trial Event A TEAM OF UP TO: 2 Team Name AVAILABLE TIME: 50 min Required Materials: Each team MUST have a protractor, ruler, non-programmable calculator, colored pencils,
More information