Summary of features – Youngest rocks at boundary, fissure eruptions typical, boundary characterised by an elevated rift valley, little or no metamorphism, shallow focus earthquakes only Example – Mid Ocean ridge, marks he divergence of several plates Transform Boundaries Summary of features: Rarely volcanism, shallow focus earthquakes, opposite and parallel movement on either side of the boundary, builds elastic potential energy until it releases in seismic waves Example – San Andreas fault
2 The movement of plates results in mountain building distinguish between mountain formed at divergent and convergent plate boundaries in terms of general rock types and structures, including folding and faulting gather, process and present information from secondary sources which compares formation, general rock type and structure of mountain belts formed as a result of thermal uplift and rifting with those resulting from different types of plate convergence Mountain building Process of formation Example Rock types Structures of mountains Thermal uplift Blue mountains Any rock type/depends on ocean/continent. No one answer Folds, faults of all types Rifting Great dividing range, rift valley Basaltic, igneous rocks Plateau, escarpments in the rift valley Oceanic – oceanic convergence Hariana trench Regional and contact metamorphic rocks. Andesite magmas Island arcs and chain Oceanic – continental convergence south America Regional and contact metamorphic rocks. Granite intrusions Intensely folded mountain ranges Continental – continental convergence Himalayas Regional metamorphic rocks Intensely folded mountain ranges - Compression forces can produce folds and faults - Rocks which bend or fold produce arches called anticlines and downfolds called synclines
Topographical monitoring – The shape of the volcano may change prior to an eruption Volcanic gases – The amount of gases released may change in particular the rate at which sulphur dioxide is produced Why people live near volcanoes Very fertile soil – new minerals are brought to surface Born in the area/family Topographic and orographic rainfall may increase amounts of water in area 9/10 people living in volcanic areas are in developing nations and are often uneducated/unaware of volcanic dangers Earthquake hazards Earthquake Nature Effect on environment Effect on people Tsunamis A series of waves caused by displacement of a large volume of water Can cause devastating damage on ecosystems and organisms, marine life, trees, land Can kill large amounts of people in coastal areas. People are swept away and buildings may collapse Building collapses Due to seismic which travel and cause to ground to shake Can destroy human environment. May pollute the biophysical environment through water and pollutants Potential loss of life, homes and economic damage Fire Caused by downed powerlines, explosions. Can spread rapidly through a destroyed city Can cause damage to human environment, may damage biophysical environment Potential loss of life, destroys homes Economic damage Liquefication Saturated soil looses strength in response to stress. Earthquakes cause water in to soil upwards to the surface Building can loose support, can cause damage to piping systems Causes death to people especially if inside a building Volcano Hazards