EQ3: How successful is the management of tectonic hazards and disasters? GapFill

Since the 1960s, there has been a large  fluctuationdecreaseincreasestability in the overall number of reported hazards.  This could be due to:

• better reporting coverage
• increased population exposed to disasters (both overall population and increased number of people living in risky, marginal areas)
• increased number of insurance claims
• increased severity of weather events

The number of volcanic disasters has been relatively  megafluctatingincreasingconstant since the 1960s.  There were very few reported volcanic disasters before this.

The number of earthquake disasters has fluctuated considerably since the 1960s, but was more constant before.

The largest events are sometimes called ‘  swarmmega-smallendemic disasters’.  They have a much larger reach than normal, affecting thousands of people across the world, cost millions (if not billions) of dollars in damage, and mean that recovery often needs support from the international community.  Luckily, such events are very rare.

Earthquakes are very difficult to predict, and offer very little warning.  Sometimes, there are smaller preceding ‘foreshocks’, and the later ‘aftershocks’ as the ground settles.  Sometimes the  foreshocksfociaftershocksepicentres can be more violent than the first earthquake.  Small earthquakes happen every day around the world, but we don’t feel most of them.

As earthquakes usually happen without any warning, they are so  successfuldangeroussafeneutral.  We spend a lot of money trying to detect signs of an impending earthquake, such as  watergassulphurradioactive emissions from the ground, and from our knowledge of tectonics and experience we know the broad regions where they occur.  Sometimes we can predict with more confidence the next part of a fault line that will be affected, but not the crucial ‘when’ part.

There are three classifications of volcano based on the likelihood of eruption.   A dormantAn effusiveAn extinctAn active volcano is either currently erupting or has erupted in the last 10,000 years.  If it’s  explosivedormantactiveeffusive, then it hasn’t erupted for 10,000 years, but we think it might erupt again.  If it’s  explosiveactiveextincthistorical, we don’t think that it’ll ever erupt again.

We can know where volcanic eruptions could occur but not when.  Based on past eruptions, including their type and frequency, we can produce a series of maps and assessments and build infrastructure.

One of the first things that might happen after an earthquake is the clearance of  ashwaterdebrislava from roads to allow access for search and rescue teams, and providers of medical aid, food and water.  If a country can’t cope with the effects of an earthquake, it may call on the international community, such as governments, charities and  fire departmentsdepartmentssecurity guardsNGOs, for help.

Risk  managementassessmentsavoidanceplans use data to estimate the cost of a disaster and can be used by planners and politicians.  However, due to the data required and time to complete, they may be narrow-focused and are rarely undertaken.  Hazard  drawingsmapsplansmodels and plans can zone an area for land use based on risk, while evacuation plans set out the procedures to be used to evacuate people in an emergency.  We can  mapmonitordrawevacuate volcanoes for signs of erupting and develop early  managementplanningdrawingwarning systems, by text alerts, etc., so that local people can take the necessary precautions when hearing about a forecast eruption on the news.

Everyone perceives a hazard differently.  There are several factors, such as the level of prediction and management, and risk-sharing (community preparedness), whereby a community comes together to reduce the risk; for example, through planning and sharing supplies and resources.