Tectonic Landforms and Hazards 1. Introduction 2. Folding and faulting 3. Reverse faults 4. Normal faults 5. Transform (strike-slip) faults 6. Tectonic hazards
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%