monitoring and prediction

• earthquakes occur without warning, although scientists can use seismometers to detect the smaller foreshocks that are often a warning of a larger quake.
• Studying historical records lets us predict where they might occur, particularly along plate boundaries where there hasn’t been much activity lately and pressure may be building up.
• Animals also exhibit strange behaviour prior to a quake as they can sense that something is wrong.
• Volcanoes give off lots of signs of imminent eruptions. They emit radon and sulphur which can be detected and also smelt, scientists can look at bulges in the dome as magma rises to the surface, and changes in temperature and gravity can be measured. The volcano may also spit out ash, smoke and lava in the days and weeks preceding a large eruption.
• cannot be reliably predicted