How did Rotorua Caldera form?
The 17-km-wide Rotorua caldera, largely filled by the waters of Lake Rotorua, was formed during the eruption of the 340 km3 Mamaku Ignimbrite about 220,000 years ago. Eruptive activity ceased during the Pleistocene, but the Mokoia lava dome, forming the island in the foreground, is less than 20,000 years old.
Is Rotorua Caldera active?
The circular depression left behind is the current caldera, about 22 km (14 mi) in diameter and now occupied by Lake Rotorua. Mokoia Island, close to the centre of the lake, is a rhyolite dome….Rotorua Caldera.
| Rotorua | |
|---|---|
| Geology | |
| Mountain type | Caldera |
| Volcanic arc/belt | Taupo Volcanic Zone |
| Last eruption | <25,000 years ago |
Is Rotorua built on a volcano?
Most people are surprised when told the city of Rotorua is built inside the crater of a dormant volcano. In fact it was one which erupted over 280,000 years ago.
How was the caldera formed?
A caldera is a large depression formed when a volcano erupts and collapses. During a volcanic eruption, magma present in the magma chamber underneath the volcano is expelled, often forcefully. When the magma chamber empties, the support that the magma had provided inside the chamber disappears.
Is Lake Rotorua an active volcano?
The circular depression left behind is the Rotorua Caldera, which is the site of the lake. Several other lakes of volcanic origin are located nearby to the east, around the base of the active volcano Mount Tarawera….
| Lake Rotorua | |
|---|---|
| Islands | Mokoia Island |
| Settlements | Rotorua, Ngongotahā |
| References |
Can you swim in Lake Rotorua?
Twelve of Rotorua’s lakes failed a key water quality test in 2018/19, but the regional council says they are currently safe to swim in. The yearly update on the lakes’ trophic levels was reported in the Bay of Plenty Regional Council’s 2018/19 Annual Report.