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VERSION:2.0
PRODID:"-//Durham University/Events"
METHOD:PUBLISH
BEGIN:VEVENT
UID:DUEVENT11887
SEQUENCE:0
DTSTAMP:20130522T074827Z
DTSTART:20120305T123000Z
DTEND:20120305T140000Z
STATUS:CONFIRMED
TRANSP:OPAQUE
LOCATION:Seminar Room 010
SUMMARY:Seminar - Wildfires and their statistical distributions: Implicati
 ons for risk, ecology and government reporting
DESCRIPTION:There is increasing evidence that the extremes of many natural
  hazards satisfy power-law or other heavy-tailed frequency-size statistics
 . Examples include earthquakes, volcanic eruptions, landslides, snow avala
 nches, forest and wildfires, meteorite impacts, and possibly floods. Altho
 ugh power-law distributions are commonly associated with the frequency-siz
 e distribution of small to large earthquakes, the frequency-size statistic
 s of many other natural hazards are frequently associated with distributio
 ns that are more thin-tailed (e.g., Gaussian or normal distributions). The
  occurrence for large and very-large events using power-law frequency-size
  distributions is often much more conservative, with a greater chance of a
  large event occurring in a given period of time, compared to thinner tail
  distributions. The choice of the statistical distribution used or assumed
  has many implications to natural hazards research.In this paper we will e
 xamine the frequency-size distributions for wildfires. Wildfires statistic
 s for the conterminous United States (U.S.) are examined in a spatially an
 d temporally explicit manner. We use a high-resolution data set consisting
  of 88,916 U.S. Department of Agriculture Forest Service wildfires over th
 e time period 1970-2000 and consider wildfire occurrence as a function of 
 ecoregion (land units classified by climate, vegetation, and topography), 
 ignition source (anthropogenic vs. lightning), and decade. For the conterm
 inous US, we (i) find that wildfires exhibit robust frequency-area power-l
 aw behaviour in 18 different ecoregions; (ii) use normalized power-law exp
 onents to compare the scaling of wildfire-burned areas between ecoregions,
  finding a systematic change from east to west; (iii) find that wildfires 
 in the eastern third of the U.S. have higher power-law exponents for anthr
 opogenic vs. lightning ignition sources; and (iv) calculate recurrence int
 ervals for wildfires of a given burned area or larger for each ecoregion, 
 allowing for the classification of wildfire regimes for probabilistic haza
 rd estimation in the same vein as is now used for earthquakes. Broadly, th
 e frequency-size distributions of wildfires have been found to be robustly
  heavy-tailed in many studies. In this study we explore the implications o
 f these statistics for risk, ecology and government reporting.
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