Tectonic Hazards gateway 2 Flashcards
How are fold mountains formed?
Fold mountains are formed along convergent plate boundaries. The compressional force causes the layers of rocks to buckle and fold. This process is known as folding. The crust is uplifted to form fold mountains.
These form along convergent plate boundaries.
How are Rift valleys and Block mountains formed?
A rift valley with steep sides formed along fault lines. A block mountain is a block of land with steep sides. Rift valleys and block mountains are formed at divergent plate boundaries. The tensional forces result in parts of the crust being fractured. Faulting forms fracture in the rocks along which the rocks are displaced. A rift valley is formed with the central block sinking relative to the surrounding blocks.
How are volcanoes formed?
volcanoes are formed by Magma is formed by the melting of mantle and crust at divergent and convergent plate boundaries. The magma rises through faults in the earth’s crust. Magma emerges onto the earth’s surface as lava, this lava then solidifies and over successive eruptions, a volcano is formed.
What are Shield Volcanoes?
Sheild volcanoes have gently sloping sides and broad summit. It is made of low-silica lava with lower viscosity (non thick, non sticky and is fluidy). It allows gases to escape easily and flows more easily through the vent ( like the urethra). Does not erupt explosively. Lava flows over a larger area before solidifying.
What are Stratovolcanoes?
Stratovolcanoes have steeper sides and a narrow summit. They are made of high-silica lava with higher viscosity (i.e Thicker, Less fluid like, Sticky). They trap gases more easily which results in pressure building up below the earth’s surface . It erupts explosively ejecting ash and rock fragments. Lava flows over a smaller area before solidifying,
What are Active volcanoes?
Active volcanoes refer to volcanoes that are currently erupting or are expected to erupt in the near future.
What are dormant volcanoes?
Dormant volcanoes are currently inactive but may erupt in the near future.
What are Extinct volcanoes?
Extinct volcanoes refer to volcanoes without current seismic activity.
What are the risks of living near volcanic areas? Destruction by volcanic materials.
Destruction by volcanic materials as rock fragments and super heated steam flow down the volcano under the force of gravity and can travel up to 80km/h destroying anything in its path. Volcanic bombs are rocks ejected forcefully during an eruption causing damage to property, these can range in size from a few centimeters to the size of cars. Landslides can occur due to the structural collapse of volcanic cone. The landslides can obstruct the flow of rivers which causes floods, block roads, and bury villages and farmlands. This may hamper rescue efforts from reaching affected areas and may destroy the livelihood of many farmers.
What are the risks of living near volcanic areas? Pollution
Pollution as ash particles from the eruption may block sunlight, suffocate crops, and cause severe respiratory problems for people and animals. The Volcanic ash can block sunlight and lower visibility making it a transport hazard
What are the risks of living near volcanic areas? Fertile volcanic soil
Lava and ash from the volcanic eruptions break down to form fertile soils making it favourable to agriculture.
What are the risks of living near volcanic areas? Building materials, precious stones
Volcanic roks can be rich in precious stones and minerals. People living around volcanoes can earn a living mining these minerals and precious stones
What are the risks of living near volcanic areas? Tourism.
Volcanic areas offer a variety of activities for tourists to engage in. People visit volcanoes because of their beautiful scenery. They are also places rich in history.
What are the risks of living near volcanic areas? Geothermal energy.
Geothermal energy is derived from the heat in the earth’s crust. The hot water or steam can be used to produce electricity
What are the factors that affect the amount of damage and casualty rates?
Magnitude, population density, time of occurrence, level of preparedness, the distance from the epicenter and the type of soil.
