A mass failure model for the initial degradation of fault scarps, with application to the 1959 scarps at Hebgen Lake, Montana

Lewis Kogan, Rebecca Bendick

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Calculation of earthquake scarp ages from scarp morphology usually assumes that scarp materials reach their angle of repose immediately after a rupture. However, observations of the 1959 Hebgen Lake, Montana, earthquake scarp and similar features worldwide confirm that scarps require a finite period of mass failure to reach the initial conditions for hillslope diffusion, so the age of features less than 1000 yr old cannot be accurately estimated with methods based only on the linear diffusion equation. We apply a numerical model of this interval of mass failure degradation to vertical initial-angle scarps from the 1959 rupture at Hebgen Lake, Montana. The mass failure rate coefficient, RM, ranges from 1:0 × 10-2 to 1.2 × 10-1m · yr-1 for young scarps at Hebgen Lake and nine other locations, and has little or no dependence on climate conditions such as annual temperature range or average rainfall. Including an interval of mass failure gives more accurate age estimates where a scarp age is of the same order as the characteristic mass failure relaxation time of 10-1000 yr.

    Original languageEnglish
    Pages (from-to)68-78
    Number of pages11
    JournalBulletin of the Seismological Society of America
    Volume101
    Issue number1
    DOIs
    StatePublished - Feb 1 2011

    Keywords

    • Raw scarp survey data and MATLAB code for the mass failure model

    Fingerprint

    Dive into the research topics of 'A mass failure model for the initial degradation of fault scarps, with application to the 1959 scarps at Hebgen Lake, Montana'. Together they form a unique fingerprint.

    Cite this