Hazards Facts

• Himalayas growing at rate of 0.5cm/yr (balanced with erosion)
• Mid ocean ridges

  • actual boundary 20-30 km wide
  • flanks may spread to width of 1500 km.
  • Peaks may reach 3000 km and highest points may rise above sea level.
• Pyroclastic flows average speeds around 60 mph but can reach 430 mph.  
• 95% of volcanoes are at plate margins (mostly destructive).
• Volcanoes are not big killers - since 1900, only Nevado del Ruiz, Colombia and Mt Pelee, Martinique have caused large numbers of deaths.
• In the past 250 years, only 5 volcanoes have killed more than 10,000 people.
• The Ring of Fire accounts for 90% of the world’s Earthquakes.
• 20,000 earthquakes globally/yr (approx. 55 per day).

  About 15 per year with magnitude 7 or higher. 
• 89% of tsunamis are caused by earthquakes.
• tsunamis average 10 feet high, but can reach 100 feet.
• About 85 tropical storms form annually.

  Of these, a little more than half (45) become tropical cyclone/hurricane/typhoon.
• For tropical storm to form: ocean temps around 27 degrees and at least 50m deep.
• Tropical storms form between 5 and 30 degrees N and S of equator
• Storm surges reach heights of 6m.
• Tropical storm causes high winds - can reach over 300km/h.

  Hurricane Patricia - 345 km/h
• 89% of wildfires are human-caused
• Smokey Bear is a 70 year-old US mascot