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Calculation of average landslide frequency using climatic records
Author(s) -
Reid Leslie M.
Publication year - 1998
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/97wr02682
Subject(s) - debris , storm , landslide , geology , climate change , debris flow , term (time) , event (particle physics) , climatology , environmental science , geomorphology , oceanography , physics , quantum mechanics
Aerial photographs are used to develop a relationship between the number of debris slides generated during a hydrologic event and the size of the event, and the long‐term average debris‐slide frequency is calculated from climate records using the relation. For a site in California with an average of 8.3 slides km −2 yr −1 , a sequence of four photo sets (representing 10–15 years, 35–50 observed slides, and 4–6 large storms) is needed to estimate the long‐term debris‐slide frequency to within 30% of the actual value ( p =0.90). If climatic records are used, a record length of 5–10 years (17–35 observed slides and 2–4 significant storms) is sufficient to provide the same accuracy. The climate‐based model suggests that debris‐slide frequency changed from approximately 1.6 to 8.3 slides km −2 yr −1 during the late 1930s owing to an increased frequency of high‐intensity storms. The model accurately predicts the change in slide‐scar density observed on sequential aerial photographs following the climatic shift.