Recent paleoseismic investigations in Northern and Western Thailand

C. H. Fenton, P. Charusiri, S. C. Wood

Abstract


Recent paleoseismic investigations have identified a number of active faults in Northern and Western Thailand.
Northern Thailand is an intraplate basin and range province, comprised of north-south-trending Cenozoic intermontane
grabens and half grabens, bounded by north- to northwest-striking normal to normal-oblique faults and
northeast-striking left-lateral strike-slip faults. The basin-bounding normal faults are marked by steep, linear
range fronts with triangular facets and wineglass canyons and have slip rates of 0.1 to 0.8 mm/yr. Based on limited
data, the average vertical displacement-per-event is about 1.0 to 1.5 m. These faults are characterized by
recurrence intervals of thousands to tens of thousands of years and are capable of generating earthquakes up to
moment magnitude (M) 7, and larger. The northeast-striking strike-slip faults are marked by shutter ridges, and
deflected drainages. Slip rates are 3 mm/yr or less. Western Thailand is dissected by a number of northwest- and
north-northwest-striking, right-lateral strike-slip faults related to the Sagaing Fault in Myanmar. Although showing
much less activity than the faults in neighboring Myanmar, these faults display abundant evidence for late
Quaternary movement, including shutter ridges, sag ponds, and laterally offset streams. The slip rate on these
faults is estimated to be 0.5 to 2.0 mm/yr. These faults are considered capable of generating maximum earthquakes
of up to M 71/2.

Keywords


paleoseismicity;active faulting;Thailand

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References


DOI: https://doi.org/10.4401/ag-3464
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Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN: 2037-416X