Topic 2 Exploring the Concepts

 

TOMOGRAPHY (“SLICE PICTURE”)

USE BEAMS THAT TRAVEL THROUGH SOMETHING AT MANY DIFFERENT ANGLES

COMBINE BEAMS FOR A DETAILED PICTURE OF VARIATIONS INSIDE

(CAT = COMPUTED AXIAL TOMOGRAPHY)

MEDICAL TOMOGRAPHY: X-RAYS (ELECTROMAGNETIC RADIATION) IMAGE VARIATIONS IN ABSORPTION DUE TO BONES, TISSUE ETC

SEISMIC TOMOGRAPHY

Seismic tomography uses seismic waves with different ray paths to map three-dimensional velocity structure in the earth

SEISMIC REFLECTION

SEISMIC REFLECTION PROFILING USES ARTIFICAL SOURCES TO GENERATE SEISMIC WAVES THAT BOUNCE OFF BOUNDARIES BETWEEN DIFFERENT TYPES OF ROCK. THE REFLECTIONS RECORDED ARE PLOTTED AS LINES ON A SEISMIC SECTION THAT SHOWS FEATURES LIKE FAULTS, FOLDS AND LITHOLOGIC BOUNDARIES.

THE TIMES OF THE REFLECTIONS GIVE THE DEPTH OF THE REFLECTING STRUCTURES

(Press & Siever)

SEISMIC REFLECTION IS THE PRINCIPAL METHOD BY WHICH THE OIL INDUSTRY EXPLORES FOR OIL- AND NATURAL GAS- TRAPPING STRUCTURES IN SEDIMENTARY BASINS AND IS ALSO USED FOR DETAILED STUDIES OF THE DEEP CRUST

SEISMIC SURVEY RESULTS

AFTER THE SEISMOGRAMS ARE COLLECTED AND PROCESSED BY POWERFUL COMPUTERS, THEY FORM SEISMIC SECTIONS

THESE SHOW STRUCTURE AT DEPTH AS AN IMAGE OF THE REFLECTED SEISMIC WAVES – CAN SEE FAULTS, FOLDS, DOMES, ETC

THESE STRUCTURES SHOW THE GEOLOGY OF AN AREA AND MAY BE “TRAPS” FOR OIL OR NATURAL GAS (WHICH CANNOT BE SEEN DIRECTLY)

(Press & Siever)

SEISMIC REFLECTION ON LAND

SEISMIC REFLECTION PROFILING IS CONDUCTED USING “VIBROSEIS” TRUCKS THAT SHAKE THE GROUND

OR EXPLOSIONS

(Cornell University)

(Lithoprobe)