8 November 2011

Rising trends in landslides in Colombia

Posted by dr-dave

Summary: A review of landslide impacts since 2002 in Colombia.

The landslides in Colombia yesterday are a reminder of the heavy toll that mass movements inflict on that country.  The largest event, at Manizales, is now known to have killed 39 people, with a further 20 still reported to be missing.  Unfortunately, this reflects a rising trend in landslide impacts in Colombia that is of great concern.  The graph below shows the recorded number of fatality-inducing landslides in Colombia from 2003 to the present, as recorded in the Durham Fatal Landslide Database.  The bar graph shows the number of recorded fatalities from landslides, whilst the line graph shows the number of recorded landslides:

The trend in the graph is clear, with an increasing landslide impact with time both in terms of numbers of events and the numbers of lives lost as a result.  Of course the data for 2011 only extends to early November (but does include the most recent events), so may well increase further.  An analysis of the timing of the landslides by month (below) shows that November is the peak landslide period (the number of landslides (i.e. the bar graph) is a better guide here than is the number of fatalities, as the latter is a much more noisy dataset):

The  causes of this dramatic rise in landslide occurrence and impacts  not clear to me, though I suspect that the usual suspects (population growth, urbanization, deforestation, road construction, etc) lie at the root of the problem.  It would be interesting to hear whether anyone based in that part of the world can comment?  What is clear is that there is an urgent need to start to reduce landslides impacts in Colombia – perhaps a programme similar to this one in Vietnam is needed.