Charlotte Bate Anika Bergen AN INTRODUCTION TO PALEOSEISMOLOGY

Charlotte Bate Anika Bergen AN INTRODUCTION TO PALEOSEISMOLOGY WITH AN EMPHASIS ON LIQUEFACTION FEATURES

PALEOSEISMOLOGY � Study of Prehistoric Earthquakes � Prehistoric: Before recorded history SEISMOLO GY

HISTORICAL SEISMIC RECORDS � United States & Co. 150 450 Wasatch Fault (Utah) � Europe 400 - 500 � China/Middle East 1000+ Teton Range Fault Zone (Wyoming) 000+ 100

CLASSIFICATION OF PALEOSEISMIC EVIDENCE 1 PRIMARY Tectonic deformation from coseismic slip SECONDARY Result of: -Earthquake shaking -Erosional and depositional consequences of shaking

PRIMARY 2 ON-FAULT 3 COSEISMIC POSTSEISMI C OFF-FAULT COSEISMIC POSTSEISMI C

EVIDENCE GEOMORPHIC -Landforms STRATIGRAPHIC -Deposits -Structures

DATING PALEOEARTHQUAKES OLDER BRACKETING FEATURE YOUNGER DATING PALEOEARTHQUAKES

RECURRENCE PATTERNS � Hazard Assessment COMPLEX

PALEOEARTHQUAKE MAGNITUDE PRIMARY / HISTORICAL EARTHQUAKES SECONDARY

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.

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