the exact formation details!!
- As mentioned before, Mt Merapi is one of the many many volcanoes in the Pacific Ring of Fire (more about this later)
- It is formed by the collision of the indo-australian plate and the eurasian plate -- with the denser indo-australian plate subducting
- As the plate subducts, it is then dipped into the asthenosphere.
- With the incredibly high temperature at the asthenosphere, the cooler lithosphere (in this case, the indo-australian plate) will undergo partial melting
- With melting of the lithosphere, this "new magma" generated is less dense then the surrounding molten rocks due to the presence of sea water and external mineral
- The sea water lowers the temperature of the molten rocks in the over-riding plate (eurasian), making the rocks denser.
- This allows the "mew magma" to make its way up to the surface
- A chain of volcanoes are formed and Mt Merapi happens to be one of them!
- by the way, the type of lava produced by such a formation (i.e. the "new magma" ) is andesitic in nature
- Andesitic lava increases the danger of the eruption
- This is so as it is more viscous as compare to basaltic lava, hence,higher chances of hazards like ashflows and pyroclastic flows
- Eruptions are also more explosive and violent due to the build up in dissolved volatiles and pressure
** The next post will give you a better description and idea of the pre-eruption proccess. namely, how did Mt merapi behave? how did the people and government react?
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