3D earthquake and fault distribution in southern California

1
3D earthquake and fault distribution in southern
California

• Michele Cooke and Scott Marshall
• University of Massachusetts

2
Faults of Southern California

• Community Fault Model

3
3D PDF

• Lots of formats out there
• VRML
• GoCad
• DXF
• 3D PDF only needs Adobe Reader 7.0 or greater to
  render

4
Earthquake Data Set

• SCEC datacenter
• http//www.data.scec.org/

5
Activity Learning Goals

• Spatial and temporal distribution of Earthquakes
  distributions reflect a dynamic system.
• Aftershocks
• Triggering
• Off-fault deformation
• Definition of active fault surfaces
• Resolution of seismic sources

6
Earthquake Data Set

• Each student assigned a set of years
• Download the earthquake catalog from those years.

7
Information on significant historic quakes

• http//www.data.scec.org/chrono_index/quakedex.htm
  l
• 1990 Upland EQ M 5.4
• 1991 Sierra Madre EQ M5.8
• 1994 Northridge EQ M6.7

8
Individual Questions

• Do some of your earthquakes appear to be
  aftershocks? How do you know this?
• Does the maximum depth of seismicity appear
  uniform across the region? What does this imply
  about the pressure an temperate conditions in the
  crust?
• Do all the quakes appear to have occurred on
  known active fault surfaces? What could account
  for earthquakes off of the mapped fault surfaces?

9
Compile all the visualizations

• Examine the spatial and temporal patterns

10
Group Questions

• For how long do the aftershocks of the Northridge
  earthquake continue?
• The Sierra Madre quake has few aftershocks
  compared to the uplands and Northridge
  earthquakes. Why?
• Do you think the CFM should include additional
  faults?
• Where would you predict earthquakes within the
  next two year period?

11
Download 3D PDFs

• ftp//eclogite.geo.umass.edu/pub/marshall/3D_Earth
  quakes/
• 3D PDFs are created using Adobe 3D software