Kaliadem - Geog investigation, identifying deposits and analyze impacts.

kaliadem is located at the base of Mt Merapi, 4km away from the peak. 
At the site, we had the opportunity to study the different types of intrusive and extrusive igneous rocks.

we were excited to be able to catch a superb view of Mt Merapi in the morning.

Amphibole (Black crystal with a 120 degree cleavage) indicate the presence of  water (Hydra minerals).  This tells us that there is a high possibility that a violent eruption happened in the area. Moisture in the minerals created more gas and bubbles, resulting in explosive eruption

Presence of lithic fragments in intrusive volcanic rock. 

Brown/orange stains on the rocks around the degassing hole, with steam still emitting from the hole.

The situation above suggested that a lot of heat is still being trapped by the rocks. The gas emitted from the hole is steam, and it contains a lot of moisture as oxidation is happening around the area, causing a brownish tint on the rocks. This shows that the eruption happened recently, and was likely a violent eruption due to the presence of large amount of moisture within the rocks.

Degassing happens after the eruption and not before, suggesting that previously gas was not able to escape due to the high viscosity of the magma, resulting in explosive eruption.

Possible investigation/inquiry questions
- Is it a recent or ancient eruption?
- Was the eruption violent or gentle?

Old vs New deposits. At the bottom we can see presence of new deposits, loose, homogenous materials with no vegetation. On the other side (top part), presence of old deposits with vegetation.

Pyroclastic deposits spread over a large, up to 15km away from the crater!! Can see the lahar flow at the left side of the middle part of the photo.

Coarse/Bigger materials such as boulders, rocks area deposited closer to the volcano. But lahar can follow the topography of the area and wash hugh boulders downstream, over long distances.

Hyperconcentrated lahar flow quickly increase their volume as they incorporate sediments of different sizes and weight along their travel paths. Highly erosive and destructive, strong enough to break and shift bridges as seen above.