charlotte bate anika bergen. study of prehistoric earthquakes prehistoric: before recorded history...
TRANSCRIPT
AN INTRODUCTION TO PALEOSEISMOLOGY WITH AN EMPHASIS ON LIQUEFACTION FEATURES
Charlotte BateAnika Bergen
PALEOSEISMOLOGY
Study of Prehistoric Earthquakes
Prehistoric: Before recorded history
SEISMOLOGY
HISTORICAL SEISMIC RECORDS
United States & Co.
Europe
China/Middle East
150450 Wasatch Fault (Utah)
400 - 500
1000+
Teton Range Fault Zone (Wyoming) 100 000+
CLASSIFICATION OF PALEOSEISMIC EVIDENCE
EVIDENCE
SECONDARYPRIMARYTectonic deformation from coseismic slip
Result of:-Earthquake shaking-Erosional and depositional consequences of shaking
1
PRIMARY
ON-FAULT OFF-FAULT
COSEISMIC POSTSEISMIC
POSTSEISMIC
COSEISMIC
2
3
EVIDENCE
GEOMORPHIC -Landforms
STRATIGRAPHIC -Deposits -Structures
DATING PALEOEARTHQUAKES
DATING PALEOEARTHQUAKES
OLDER
BRACKETING
YOUNGER
FEATURE
RECURRENCE PATTERNS
Hazard Assessment
COMPLEX
PALEOEARTHQUAKE MAGNITUDE
PRIMARY SECONDARY
HISTORICAL EARTHQUAKES
/
NEW MADRID SEISMIC ZONE
Pink dots represent epicenters of earthquakes since 1974.
Black crosses represent large earthquakes in the area.
Sand blows appear as white deposits in a variety of shapes and sizes.
Sand blows in the NMSZ could be as large as 10 000 square kilometers.
Layering within the dike and the sill indicate that liquefied sand travelled to the surface on multiple occasions.
Archeological artifacts found in the NMSZ.
Archeological artifacts and radiocarbon dating help put time constraints on the sand blows.
B: Average recurrence of earthquakes in the area is 500 years.
http://www.youtube.com/watch?v=ksaHZy2JHK0