1. Introduction 2. Folding and faulting 3. Reverse...
Transcript of 1. Introduction 2. Folding and faulting 3. Reverse...
Tectonic Landforms and Hazards
1. Introduction
2. Folding and faulting
3. Reverse faults
4. Normal faults
5. Transform (strike-slip) faults
6. Tectonic hazards
OROGENIES and OROGENESIS
Examples (Christopherson, 2012, p. 343-345):
1. Laramide orogeny (Rockies), 40-80 my BP
2. Nevadan orogeny, 29-35 my BP
3. Allegheny orogeny (Appalachians), 250-300
my BP
4. Alpine orogeny (European Alps), 2-66 my BP
5. Himalayan orogeny, 45-54 my BP
Compressional force
Anticline
Syncline
Asymmetric/recumbent folds
(overturned anticline)
Development of folds due to compression.
Compressional force Fault plane
Development of a fault from folding: a reverse
(thrust) fault, the result of compression.
Fault plane
Reverse (thrust) fault: result
of compressional stress. Source: Christopherson, 2012, p.342.
Transform (strike-slip) fault: result of lateral
(shearing) stress. Source: Christopherson, 2012, p.342.
Fault plane
Reverse (thrust) fault: result
of compressional stress. Source: Christopherson, 2012, p.342.
Fault scarp
produced by a
reverse (thrust)
fault in Algeria,
following
magnitude 7.3
earthquake, 1980. Source: Bloom, 1998; photo by M.
Meghraoui.
Source: David Schultz, Pictures from 2002 Winter Olympic Weather Forecaster Training
http://www.cimms.ou.edu/~schultz/olympics/images/img20.gif
Aerial photo of Weber Canyon and the Wasatch Front.
Graben (down-faulted block)
Horst (up-faulted block)
Horst and graben: features of extensional stress. Source: Christopherson, 2012, p.345.
Transform (strike-slip) fault: result of lateral
(shearing) stress. Source: Christopherson, 2012, p.342.
Effects of a transform fault, southern California.
Source: Cornell University Geology Department, Geo 101 image gallery.
Effects of the San Andreas fault.
Source: University of Washington Department of Geophysics, magnetotellurics research.
Focus
Epicentre
Focus and epicentre at the Loma Prieta
earthquake, CA, 1989. Source: Christopherson, 2012, p. 350.
Liquefaction
potential map for
Salt Lake County.
Source: Utah Geological Survey.
High: 50% in 100 years
Moderate: 10-50%
Low: 5-10%
Very low: less than 5%