Natural Hazards Observer Volume 23 No 6

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ISBN 13 :
Total Pages : 28 pages
Book Rating : 4.:/5 (946 download)

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Download or read book Natural Hazards Observer. Volume 24, Number 6, July 2000 written by and published by . This book was released on 2000 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Not all hazard-generating processes are independent of time or human influence. Even if hazards did not vary with time, the associated risks would inevitably increase since populations and hazard-exposed assets increase with time. - Yet, do we allow for these sometimes human-induced factors in our risk mitigation policies and actions? Not as much as we should. Quantitative probabilistic hazard assessment is generally based on the record of past hazardous events and used to account for present and near future hazards. However, the catalog of hazardous events is not always the only input to the assessment. Sometimes, generalized models based on the historic record that account for the physical processes in the region are used. To be maximally effective, the latest scientific knowledge must be applied when estimating future hazards and risks. Take, for instance, National Flood Insurance Program (NFIP) maps. For most localities, flood zones were mapped many decades ago. Since then, in many of the most rapidly developing regions of the U.S., land-use patterns have drastically changed, altering the ability of the land to absorb high amounts of precipitation and to extend the duration of run-off in rivers and floodplains. Flooding beyond designated flood zones appears to be increasing, although systematic surveys to confirm this notion are generally lacking. Hence, flood-zone mapping does not depict the present state of the hazard, nor have we evaluated other increasing risk exposures threatening many parts of the U.S.