Thus, Sakurajima has caused a series of disasters such as the eruption in 1914 which killed 58 people [4] and sank the magma chamber by 60 cm.

The supervolcano peaks at 1117 m.[6] The eruption forming the Aira Caldera, occurred approximately 30,000 years ago, and resulted in tephra and ignimbrite from a vast amount of magma affecting the nearby land.

The eruption also aided in the formation of the 200 m (660 ft) deep Kinko Bay which formed after sea water entered the area.

[9] Such diffuse non directional pyroclastic flows, overwhelming the local landscape, have now also been described in New Zealand, for example in the Hatepe eruption.

[14] Before the initial eruption of 25,000 years ago there was a wide and shallow basin of nearly the same size as the present Aira Caldera occupying the northern end of Kagoshima Bay with an east–west orientation.

[9] The Tsumaya pyroclastic flow consists of a "pale pinkish brown glass matrix containing a small amount of pumice and lithic fragments"[9] consistent with the Osumi pumice fall and the Tsumaya pyroclastic flow occurred from the same vent.

There was only a very short period between the Tsumaya pyroclastic flow and the formation of the present caldera in the Ito eruption.

The connection between Aira and Kirishima represents the clearest example of volcano interconnectivity revealed by geodetic monitoring.

[15] Aira Caldera and Kirishima's magma storage is linked through tunnels that extend horizontally over tens of kilometers which is able to be explained through the presence of hotspots.

[15] The magma storage underlying Aira Caldera has been feeding into the stratovolcano Sakurajima, expanding over time.

However, there have been points in time where the chamber has deflated as a result of eruptions releasing the pressure built which cannot be explained by stress changes.

A prime example is the Sakurajima eruption in 1914 (approximately 1.5 km3 in volume), which caused the magma chamber to sink 60 cm.

[4] For this amount of magma to erupt, it would take approximately 130 years for the chamber to refill as according to Dr James Hickey and his co-authors.

Recent GPS deformation measurements, amalgamated with geophysical data and computer modelling enable the reconstruction of the magma system beneath the caldera.

[4] Dr Haruhisa Nakamichi, Associate Professor at the Disaster Prevention Research Institute, Kyoto University, and co-author, said: "It is already passed by 100 years since the 1914 eruption, less than 30 years is left until a next expected big eruption, Kagoshima city office has prepared new evacuation plans from Sakurajima, after experiences of evacuation of the crisis in August 2015.

"[4] A group of scientists led by Dr Dominique Remy used Synthetique Aperture Radar (SAR) to detect levels of inflation of Aira Caldera over the Kokubu urban district.

[3] Rare minerals exist on the sea bottom with hydrothermal vents including volcanic chimneys.