Post-supereruption recovery at Toba Caldera

Area of Science:

• Volcanology
• Geochronology
• Geochemistry

Background:

• Large calderas, or supervolcanoes, pose catastrophic hazards, but post-eruption activity (resurgence) is poorly understood.
• The Toba Caldera, Indonesia, experienced a massive eruption ~74,000 years ago, followed by a period of resurgence with an unclear magmatic and uplift history.

Purpose of the Study:

• To clarify the temporal details and progression of post-supereruption resurgence at Toba Caldera.
• To investigate the magmatic history and uplift patterns following the Toba supereruption.
• To explore the connection between Toba Caldera's magma reservoir and the Sinabung stratovolcano.

Main Methods:

• Dating of resurgence using radiocarbon (¹⁴C), zircon U-Th crystallization, and (U-Th)/He ages.
• Analysis of post-caldera effusive lava eruptions and uplifted lake sediments.
• Geochemical analysis of volcanic products and zircon dating from Sinabung.

Main Results:

• Resurgence at Toba Caldera initiated at 69.7±4.5 ka and persisted until at least ~2.7 ka.
• Resurgence progressed westward across the caldera, evidenced by lava flows and uplifted sediments.
• Geochemical data and zircon ages suggest Toba's magma reservoir extends beneath Sinabung, influencing its eruptions.

Conclusions:

• The Toba Caldera has undergone prolonged resurgence for over 60,000 years, significantly shaping its post-supereruption landscape.
• Understanding Toba's resurgence provides crucial insights into supervolcano dynamics and hazard assessment.
• The findings highlight a potential link between the Toba magma system and ongoing activity at Sinabung volcano.