Central New York Association of Professional Geologists

November Meeting:David Barclay, SUNY Cortland. Megathrusts and tree-rings: high precision dating of the penultimate great earthquake in southern Alaska

  • Wednesday, November 02, 2022
  • 5:00 PM - 8:30 PM
  • Spaghetti Warehouse

Registration

  • Two free dinners are available on a first-come, first-served basis for student members of CNYAPG. The free dinners are sponsored by Corporate Donors.
  • This category is for Student member's attending the dinner meeting.
  • This category is for student non-members attending the dinner meeting.
  • This category is for members attending the dinner meeting who do NOT want to collect a CEU
  • This category is for members attending the dinner meeting who do want to collect a CEU
  • This category is for non-members attending the dinner meeting who do NOT want to collect a CEU
  • This category is for non-members attending the dinner meeting who do want to collect a CEU
  • Reserved for the speaker to gain CEU credit for the presentation
  • This registration type is for those who wish to attend the talk virtually without earning NYS Professional Geologist continuing education credits (CEUs)
  • This category is for members attending the virtual meeting who do want to collect a CEU
  • This category is for members attending the virtual meeting who do want to collect a CEU

Registration is closed

5:00-6:00 PM Networking

6:00-7:00 PM Dinner

7:00-8:00 PM Presentation

Abstract:

Megathrusts and tree-rings: high precision dating of the penultimate great earthquake in southern Alaska

A “ghost forest” of dead trees at Girdwood in Alaska records coseismic subsidence from the March 1964 M9.2 earthquake. Below the roots of these trees, a buried layer of stumps records similar coastal subsidence during the penultimate great earthquake here about 700-900 years ago. This talk will describe ongoing efforts to obtain a precise kill-date for these older stumps using tree-ring crossdating and radiocarbon wiggle-matching. A precise date would give the exact year of the penultimate great earthquake, show the length of the most recent cycle of stress accumulation and release for the northeastern end of the Alaska-Aleutian megathrust, and enable future studies to document regional evidence for coseismic land disturbance from the penultimate great earthquake. In addition to these outcomes for paleoseismology, this work is giving insight into tree-ring crossdating in the rugged maritime area of southern Alaska and into apparent offsets between radiocarbon ages in coastal Alaska and the IntCal20 calibration curve.

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  • November Meeting:David Barclay, SUNY Cortland. Megathrusts and tree-rings: high precision dating of the penultimate great earthquake in southern Alaska
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