The flat cone of the volcano Mount Bromo rises in the east of Java. It is located in the Tengger Caldera along with three other volcanoes. This multiple caldera has a diameter of 16 km and is 110 meters deep.
The genesis of the Tengger caldera was divided into several stages and developed from 5 stratovolcanoes, which all ended in a caldera. These calderas overlap each other today.
First a 4500 m high volcano formed about 820,000 years ago, which collapsed after a large volcanic eruption about 150,000 years ago and formed a first caldera. Later eruptions deposited thick layers of ignimbrite. A phase of strong eruptions in the early Holocene created the youngest caldera, called the Sand Sea Caldera (Segara Wedi), which measures 8.5 x 10 kilometres. The term fog sea caldera would be almost more appropriate, because thick fog often passes through the caldera during dawn.
Bromo pictures
After a longer pause in the eruption, the activity in the Tengger caldera revived and the new eruption centres grew. In addition to the already mentioned volcanic cones, two more volcanoes formed at the southeastern caldera rim.
Part of this volcanic complex is the 3,676 m high Semeru, which lies a few kilometres northwest of the Tengger caldera. Together these volcanoes form the Bromo-Tengger-Semeru massif.
Bromo is the youngest crater cone in the Sand Sea Caldera. Its peak height is reported to be 2,329 m, in fact the young volcanic cone itself rises less than 100 m from the bottom of the caldera.
Since 1767, more than 60 eruptive phases of Mount Bromo have been recorded. Most eruptions are strombolian and occasionally have volcanic or phreatic characteristics.
In June 2004, two people died in an unexpected eruption. The last eruption took place in 2010 and was preceded by a period of increased seismic activity. The first eruption occurred at the end of November, which propelled ash up to 500 m high causing the temporary closure of the Malang Regional Airport. On 20 December the eruption cloud reached a height of 800 meters. The eruption did not end till early summer in 2011.
Mount Bromo was named after the Hindu god Brahma. At the foot of Mount Bromo, a temple was built and is the beginning of a pilgrimage path. Each year, thousands of believers gather on the crater rim on the occasion of the Kasada Festival to make offerings. A staircase with 241 steps leads up to the crater rim: from there you can view a steaming fissure vent.
