The causes of tectonic hazards GapFill

Earthquakes and volcanoes typically occur along  continentalplatecentrePacific boundaries. These are at the  middlecentrerightedges of the plates. For example, they can be seen as a so-called 'ring of fire' around the  shallow oceanconservative plateIndian OceanPacific Ocean. Plate boundaries can be categorised according to type: Some are termed  divergentshallowmantlevolcanic. Here, the plates are forced apart by convection currents in the  lavacoremantlecrust. There can be  continentalcoreshallowdeep focus earthquakes, which occur as the plates move.  CoreLavaBoundariesMagma rises to fill the gaps between plates. This forms basic lava volcanoes such as Surtsey, off the coast of  AngleseaAmericaAfricaIceland. Some boundaries are termed convergent. Here, the plates are pushing into each other. There can be  biggerswelldeepshallow focus earthquakes in the subduction zone where the  crustbiggerdenserMontserrat oceanic plate is forced under the lighter continental plate. In the subduction zone, the  mantleIndianoceaniccontinental plate melts and magma rises to the surface. This process forms explosive volcanoes such as Soufrière Hills,  MontserratGozoIcelandHawaii. At other boundaries, land is neither created nor destroyed as the plates move past each other, or move at different speeds - we call these   volcanicconservativedivergentsubduction boundaries. A famous example is the San Andreas Fault in   CaledoniaCaliforniaChileConiston. They appear as fault lines on the surface - there can be powerful earthquakes, but not volcanoes.