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Geology Flores Indonesia, Volcanic Eruptions Indonesia

Geology Flores Indonesia, Volcanic Eruptions Indonesia

General tectonic information
Dynamic geological transformations during early Pleistocene period (1.8 million years ago) that included significant tectonic movements with corresponding volcanic activities, and extremely large sea level fluctuations played a major role in shaping the current geological formations found throughout Indonesia.
Indonesia is located within the subduction zone of a number of different tectonic plates (i.e. Eurasia, Pacific, Indian-Australian and Philippine-plates). A subduction zone is a tectonically active zone where two ore more different plates collide. The heavier plate (oceanic plate) sinks under the lighter plate (continental plate) and melts in the heat of a layer of liquid aestenosphere. Near the edge of these plates the volcanic activity is typically very high due to the pressure, friction and the melting plate edges. Another consequence of these tectonically active zones are oceanic trenches and ridges, folds, mountains, volcanoes, earth-quakes and tsunamis.
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The multi-coloured lakes of Kelimutu volcano, near Ende
Cunca Wulang waterfall, near Labuan Bajo

High sea level fluctuations occurring approximately 18,000 years ago allowed the migration of fauna among the islands of Java, Sumatra and Kalimantan. Not evidenced today, but assumed to be a highly plausible scenario, was the migration of surface fauna between the islands of Flores and Komodo in this period. The sea level was at that time 85 m lower than it is today.

Flores belongs to a highly tectonically active region where three major plates meet and collide.

Indonesia counts 129 volcanoes. 13% of all the active volcanoes in the world exist in Indonesia. One of the most tectonically active places in the world, Indonesia is prone to the resultant natural disaster of earthquakes, tsunamis and volcanic eruptions. Indonesia occupies a large section of what is known as the ring of fire.

Flores is home to several volcanoes: Kelimutu (Ende), Inerie and Inelika (District of Ngada), Anaka (District of Manggarai), Rokatenda (District of Sikka), and Ilemandiri (East Flores). Although the volcanoes in West Manggarai are not currently classified as ‘’active,’’ there exists a number of post-volcanic formations – such as calderas, basalt columns and volcanic lakes.

Major tectonic plates and subduction zones of Australasia
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Hot spring found next to one of the deepest volcanic crater lakes in the world at Sano Nggoang, near Labuan Bajo
Cunca Rami waterfall near Werang, West Flores

Natural Disasters
A strong movement of the Philippine plate on December 12, 1992 caused an earth-quake measuring 6.8 SR with an epicenter in the Flores Ocean at a depth of 37 km. This earthquake caused a massive tsunami which caused widespread loss of life and property damage, especially in Maumere and the surrounding Sikka regency. An estimated 2,500 people died and 90,000 were left homeless by the earthquake, tsunami and landslide that accompanied this disaster.

In addition to direct effects of tectonic events, such as earthquakes and volcanic eruptions, there are also frequent landslides, floods and prolonged period of draughts.
The government of West Manggarai continues to improve monitoring and early warning systems in an attempt to mitigate the effects of future natural disasters.

A forest of petrified wood near Labuan Bajo
The dominant stone formations found in the district of West Manggarai are volcanic in nature including andesite, effusive dastic tuff, volcanic sediments as well as lime /carbonate stone formations comprised of karst and coral. Metamorphic stone formations can also be found in this region.

Geo-tourism Potentials

The region of West Manggarai is rich in different types of stone formations, forming the basis of the varied natural landscape of this area. Karst formations, such as caves, travertine, stalactite and stalagmite suggest a yet-to-be-realized huge geo-tourism potential for this area. Other geo-tourism phenomenon, such as forests of fossil wood, crater lakes, and dramatic stone formations carved out by eons of water and wind represent strong potential draws for future tourists.

Nature’s handiwork in a time-worn stone formation of West Flores