Ali Onceloncel@kfupm.edu.saDepartment of Earth SciencesKFUPMGravity and IsostasyIntroduction to GeophysicsIntroduction to Geophysics-KFUPMPrevious LectureGravity UnitsExample 1: Marss t!in moons Example ": $he %alley and &id'e Province (1-) m'als* +ensitivity: ,ensity ,istri-ution+ensitive to chan'es in Mass (,ensity* chan'es ,ensities o. Geolo'ical Materials /n-Line Gravity Map 0onstruction $ool0olor ta-le .or standard Gravity map Example 1: 1orth 2natolian Fault 3one in the sea o. Marmara Example ": Gha!ar re'ion o. +audi 2ra-ia Introduction to Geophysics-KFUPMParks and Plates,pp.272005 Robert J. Lillie Introduction to Geophysics-KFUPMParks and Plates2005 Robert J. LillieParks and Plates2005 Robert J. Lillie Introduction to Geophysics-KFUPMhttp://www.moorlandschool.co.uk/earth/tectonic.htmIntroduction to Geophysics-KFUPM1977, Marie ThorpeParks and Plates2005 Robert J. Lillie$opo'raphy o. the /cean FloorIntroduction to Geophysics-KFUPMNational

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d$inistration $!o Forms o. Isostatic Upli.tpp.2% Parks and Plates 2005 Robert J. LillieIntroduction to Geophysics-KFUPMLow density due to higher temperaturehttp://www.moorlandschool.co.uk/earth/tectonic.htm$!o Forms o. Isostatic Upli.tIntroduction to Geophysics-KFUPM4hat is Isostatic E5uili-rium6 7 0rust .loats on Mantle (hydrodynamic e5uili-rium*7 +ur.ace elevation is .unction o. underlyin' mass (thic8ness and density o. crust*7 +ur.ace elevation is compensated -y mass -elo! itIntroduction to Geophysics-KFUPM9ou'uer 2nomaly7+li'htly positive over oceans7+li'htly ne'ative over continents4hy67 9ecause a uni.orm density !as used in InternationalGravity Formula":;< '=cm>>:> '=cm>Mantlehttp://www.moorlandschool.co.uk/earth/tectonic.htmIntroduction to Geophysics-KFUPMExample .rom 2ra-iaAB0

!A BDistance (km)Depth (km)0500 1000 15002000Bouguer GraviyMgal0500 1000 150020001000-100Introduction to Geophysics-KFUPMExample .rom 2ra-iaAB0

!ABDistance (km)Depth (km)0500 1000 15002000,ata +ource: 0ornell University7 9ou'uer anomalies that are ne'ative over hi'h areas and positive over oceans:71ear sea level? the avera'e is close to @ero:7 $he ne'ative 9ou'uer anomalies areas due to the excess o. lo! density material at depth in mountainous re'ions !hen compared to roc8s at depth in areas o. lo! relie. near sea level:Introduction to Geophysics-KFUPMHomework, Due to May 17Use the online tool .or ma8in' a 'ravity map .rom the site http:==!!!:itismolinari:mi:it=Gravity:htm:Ma8e your 'ravity map and compare chan'es in the 'ravity to chan'es throu'h re'ions o. maAor tectonics64hat is the 'ravity throu'h the areas: a* &ed +ea -* ,ead +ea Fault c* Iranian +ea d* Gul. o. 25a-a e* 3a'ros $hrust FoldIntroduction to Geophysics-KFUPM$he 5ui@ o. the !ee8For the .ollo!in' e5uation? de.ine the varia-les:F22B 'o-s C 'th DF2092 B F22 C 90 D $0Introduction to Geophysics-KFUPM