The current geological formations found in Flores and throughout Indonesia were predominantly shaped by dynamic geological transformations during the early Pleistocene period (1.8 million years ago). These transformations included significant tectonic movements with corresponding volcanic activities and extremely high sea-level fluctuations.
A craggy mountainous landscape reflects the island’s turbulent geological history in the midst of the so-called ‘Ring of Fire’, a geologically unstable hot-spot. Flores is part of a volcanic belt which stretches from Sumatra through Java and Bali to the Banda Sea. The island’s highest, still active volcanoes are Mount Egon (1703m) in Maumere and Mount Inerie (2245m) in the Ngada district. However, the most famous volcano is Kelimutu with its tri-colored crater lakes, shimmering in green, turquoise, and black-red. Although many of the volcanoes in Flores are not classified as active, they display a number of post-volcanic formations worth seeing, such as calderas, basalt columns, and volcanic lakes.
The volcanic activity is strongly linked to the island’s position in a subduction zone, which is a tectonically active spot where a number of different tectonic plates – the Eurasian, Pacific, Indian-Australian, and Philippino plates – collide. There, the heavier oceanic plate sinks under the lighter continental plate, where they melt in the heat of a layer of liquid asthenosphere. The emerging pressure, friction, and melting processes at the edge of these plates often cause volcanic eruptions, earthquakes, and tsunamis. Flores is very prone to these natural powers that sometimes cause major disasters: in 1992, a strong earthquake, followed by a massive tidal wave, claimed the lives of 3,000 people and destroyed the town of Maumere and its surroundings.