T211 The Geological Signature of Natural Hazard Events I

Tuesday, 24 October 2017
8:00 AM - 12:00 PM
Chelan 5

MILLENNIAL ARCTIC, TEMPERATE, AND TROPICAL STORM RECONSTRUCTIONS; FREQUENCY, PERIODICITY, AND TELECONNECTIONS

Paper number: T211-12
Program: Technical Sessions
Time: 10:50 AM – 11:10 AM

Authors

Abstract

Climate controls on hurricane variability and storminess have critical implications for society and are not well understood. To some extent, our understanding of the role climate dynamics play in driving changes in storminess are hampered by the short observational record and often incomplete historical record which make it difficult to examine temporal and spatial trends in severe storm frequency and periodicity. To address this, we discuss a synthesis of arctic (Alaska), temperate (New England), and Tropical (Belize) storm reconstructions spanning several thousand years. The records encompass a variety of depositional settings including a fjord, back-barrier pond, and atoll/cay. Storm reconstructions are developed using coarse fraction grain size analysis and chronological control from pollution and radiocarbon dating of sediment cores ranging from 5-9m. In some cases well resolved modern storms captured in the stratigraphic record provide the context on which to base the potential strength/magnitude of storms in the pre-historic storm record. For example, in several instances, periods in the pre-historic record show evidence of more powerful storms (thicker and coarser grain sizes in event beds) than the historic archive and much more powerful than present day events. Clearly coastal hazard assessments based solely on historic storm records capture only a small fraction of the potential storm scenarios a given coast may experience and likely underrepresent the largest of these events, especially given the potential for a future of increased warming. Diagnostic forcing mechanisms responsible for significant variability in event bed deposition may include, but are not limited to, changes in Hadley Cell circulation and El Nino as well as increases in sea surface temperatures in the main development regions or in proximity to the site.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-300696

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