Applying physics to the earth to understand its elements Understanding the structure of other planets / moons Geophysics has been part of space shuttle and moon landing programs
See crust of the earth on a large scale in map view Continents and mid oceanic ridge Continental drift, earth is in motion [this theory did not become accepted theory until the early 70’s] Earthquakes, tsunamis, mountain building Earthquake in Indian Ocean caused tsunami Boxing Day 2004 USGS recorded that earthquake had happened and thought a tsunami was likely but had no-one to contact on Boxing Day [no early warning] Geophysicists monitor and measure the earth’s movement [time of travel of earthquake energy]
Whole earth Earth has a radius of 6,400 km, composed of core, mantle and crust
There are many different areas of study in geophysics. One other area is in the study of natural hazards. The University of Calgary is involved in seismic monitoring of Turtle Mountain, where Frank Slide occurred.
Exploration Geophysicist uses geophysics to find oil and gas Drilling rig, production platform, seismic ship in background
This illustration shows a real marine survey with an example of the type of seismic data that would be recorded. Have you ever wondered how anyone ever figured out exactly where an offshore well should be drilled? This is an example of how we apply physics to the earth to find the best place to drill We measure where the rock layer change – the interfaces We don’t see oil, or gas, or water; we see the difference in the rock physics Photo courtesy Veritas
Diagram of what we will be looking at on the field trip, a lot of preparation is required to get to this point Energy source, recording devices, recording truck Trace the path of the energy Some reflected, some transmitted
Energy sources Vibroseis shakes the earth Work all over the world – Canada and Middle East
Laying out geophones In old days used to have wide, high-impact cut lines Today, in environmentally sensitive areas we use hand cut, low-impact cut lines; supported by helicopters, not as much heavy equipment * As a geophysicist, your responsibility to ensure that work is done in environmentally sensitive manner
Some areas we acquire seismic are very rugged Need to be physically fit to work in the field Safety is very important Moving into tougher areas to explore since easier areas have been evaluated
Acquired data is processed at data processing centres in the office Geophysicist at top right is building a velocity model to get better data to analyze Technologists often process as well
Exploration geophysicists Interpreter works with a geologist to understand what kind of features we might expect to see in the subsurface Here is what a modern reef looks like today [Belize] Reef margin and deep water to top of picture; beach is back toward the photographer The sides of the cube are seismic profiles of the subsurface The surfaces are interpreted to be a boundary between rock layers with different physical properties Here is what an ancient buried reef might look like; we try to drill a well into the reef; one or two wells just missed or are on the flank Photo courtesy Lindsay Dunn, geologist
Exploration geophysicists Interpreter analyzes the finished processed data to get an image of the subsurface A buried mountain – similar to what you see on the way to Banff Back is vertical slice through the earth, coloured is a representation of a buried surface Oil floats on water, and gas rises above oil; geophysicists look for high points where oil and gas would be found If you want water, drill the lows
Exploration geophysicists Subsurface structure is not necessarily the same as the structure at the surface Communicating the ideas, making decisions, teamwork All types of people from all over the world Photo courtesy Veritas
Remote sensing used to understand the earth Helpful in evaluating large areas Aeromag data can be used in exploring for minerals
Other applications for geophysics Resistivity well logging tool
Other applications for geophysics GPR Dr. Paul Bauman
When not in the classroom, will also do some project work U of C student GPR on Ellesmere Island
When not in a classroom Moose Mountain field trip out near Bragg Creek, Alberta [west of Calgary]
Learn about field operations, how data is gathered
Data processing Data management Support the geophysicist A lot of expertise in specific technology [Similar to relationship between nurses and doctors]
Slide has averages, some get paid more, some get paid less
