Title: Characterizing%20Fault%20Populations%20and%20Seismicity%20on%20an%20Active%20Plate%20Boundary%20Using%20GIS
1Characterizing Fault Populations and Seismicity
on an Active Plate Boundary Using GIS
- Tip Meckel
- Ph.D. Candidate
- Geological Sciences
2Outline
- Reasons for study
- The Macquarie Ridge Plate Boundary
- Data Sets Involved in Study
- GIS Project
- Results and Significance
- Conclusions
3Why Study Plate Boundaries?
Better understanding of tectonics is important!
Images courtesy of USGS unless noted otherwise
4What are plate boundaries?
5The Macquarie Ridge Plate Boundary
- Benefits of studying this boundary
- Similar to San Andreas Boundary
- It is completely naked!
6Flying over the Macquarie Ridge!
Movie courtesy of the Australian Geological Survey
7Why use GIS?
- Interpretations rely heavily on maps
- advantage to having data incorporated into map in
table form - Spatial analysis of features and associated data
8Data sets using
- Entire Dissertation
- Remotely Sensed Data from Ship Bathymetry,
Sidescan Sonar, Gravity, Magnetics, and Seismic. - GIS Project
- Line coverage of Faults interpreted on seafloor
- Point coverage earthquake data from USGS
- Bathymetry?
9GIS Project
- Import line drawing into Arc Format
- Convert line drawing to ASCII and import
- Thanks to Christina Massell and Chris McFarlane
- Obtain USGS earthquake data and convert to a
point coverage in correct latitude /longitude
projection - Use data table to color earthquakes according to
magnitude and depth
10GIS Results I
11GIS Results II
12Faults greater than 0.231 units
13Earthquake occurrence by year
14Earthquake occurrence by depth
15CONCLUSIONS
- The lengths of faults follow an exponential
distribution - this has not been documented and
may be suggestive of fundamental processes at
plate boundaries. - The spatial occurrence of earthquakes over time
and with depth is NOT random. This likely
indicates the current state of stress at the
plate boundary. There may yet be some hope for
more complete understanding of tectonics!
16Future Directions
- Incorporate bathymetry, gravity and magnetic data
into map. This has thus far been stymied by the
format of the ship data. - Pursue ideas generated by distribution of fault
length data. What can the distribution tell us
about fundamental faulting processes at plate
boundaries?