Charlotte Bate Anika Bergen. Study of Prehistoric Earthquakes Prehistoric: Before recorded history...

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