Cosmogenic nuclide Helium 3 (³He) exposure dating of fault scarps in a young basaltic environment, The Hat Creek Graben, North East California

Forbes, Victoria (2017) Cosmogenic nuclide Helium 3 (³He) exposure dating of fault scarps in a young basaltic environment, The Hat Creek Graben, North East California. MSc(R) thesis, University of Glasgow.

Due to Embargo and/or Third Party Copyright restrictions, this thesis is not available in this service.
Printed Thesis Information: https://eleanor.lib.gla.ac.uk/record=b3288233

Abstract

This study investigates the seismic history of the Rocky Ledge, Old Lumber Mill and Arkwright Flat faults in the Hat Creek Graben, north east California, in order to understand the interaction of faults in this tectonically active and geologically unique area. Probabilistic seismic hazard analysis outputs are used to inform building codes in areas of tectonic activity to minimise the hazard presented by seismic shaking. Quantitative data can be used to increase the accuracy of these models, reducing the hazard. Using the well-established method of surface exposure dating of normal fault feature using cosmogenic Helium 3, a seismic history of the graben is established. Groups of calculated exposure ages at 51ka, 32ka and 12ka give a deduced possible recurrence interval of 20ka. The associated hazard curve gives a peak ground acceleration of 0.7g for a 20ka recurrence interval. The calculated exposure ages also confirm the accuracy of previously calculated 40Ar/39Ar ages for the Rocky Ledge basalt. Exposure dating of the flow top surface confirms minimal erosion since emplacement, reinforcing the accuracy of the exposure ages calculated. The study shows the importance of geomorphological tools in seismic investigations, as historical records and geophysical evidence do not often span recurrence interval time scales.

Item Type: Thesis (MSc(R))
Qualification Level: Masters
Additional Information: Due to copyright restrictions the full text of this thesis cannot be made available online. Access to the printed version is available once any embargo periods have expired.
Keywords: Cosmogenic nuclides, Helium 3, exposure dating, probabilistic seismic hazard analysis, basalt, regional tectonics, normal fault, recurrence interval, Hat Creek graben, Old Lumber Mill, Rocky Ledge, Arkwright Flat, seismicity, noble gas mass spectrometry.
Subjects: Q Science > QE Geology
Colleges/Schools: College of Science and Engineering > School of Geographical and Earth Sciences > Earth Sciences
Supervisor's Name: Persano, Dr. Cristina
Date of Award: 2017
Embargo Date: 21 September 2027
Depositing User: Miss Victoria Forbes
Unique ID: glathesis:2017-8417
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 24 Oct 2017 14:03
Last Modified: 10 Nov 2017 11:53
URI: http://theses.gla.ac.uk/id/eprint/8417

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