Skip to content

Magma Storage Conditions Beneath Krakatau, Indonesia: Insight from Geochemistry and Rock Magnetism Studies Aditya

Aditya Pratama1, Dini Nurfiani1, Putu Billy Suryanata2, Taufik Ismail1, Gabriela Nogo Retnaningyas Bunga Naen1, Mirzam Abdurrachman3, Wilfridus Ferdinando Supriyadi Banggur1, Nining Sumawati Asri4, Ratika Benita Nareswari1, Satria Bijaksana2, Muhammad Hanif1, Estu Kriswati1, Idham Andri Kurniawan4, Nugroho Imam Setiawan5

  • Affiliations: 1Research Center for Geological Disaster, National Research and Innovation Agency (BRIN), Bandung, Indonesia; 2Faculty of Mining and Petroleum Engineering, Bandung Institute of Technology, Bandung, Indonesia; 3Faculty of Earth Sciences and Technology, Bandung Institute of Technology, Bandung, Indonesia; 4Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), Tangerang Selatan, Indonesia; 5Geological Engineering Department, Engineering Faculty, Universitas Gadjah Mada, Yogyakarta, Indonesia

  • Presentation type: Poster

  • Presentation time: Thursday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 248

  • Programme No: 1.1.34

  • Theme 1 > Session 1

Abstract

Krakatau volcano is characterized by cyclic phases of growth and destruction of the edifice. A volcanostratigraphic study identified three eruptive periods: Old, Young, and Anak Krakatau. The Old and Young Krakatau periods ended with the first and second Caldera Forming Eruption respectively. Due to its permanent activity and edifice evolution, Krakatau poses a high risk on the surrounding inhabited islands. In this study, we combined geochemistry, rock magnetic, and petrology to infer the evolution of magma storage conditions from Old to Anak Krakatau periods. This study is the first to report on the chemical and rock magnetic characteristics, as well as storage system conditions of Old Krakatau and its relation to the ongoing evolution of Krakatau. Our data show that:1) Old and Young Krakatau magma storage regions are shallow (within the upper 3 km), contain more differentiated magmas, from which the Old Krakatau magmas may be less oxidized and had lower temperatures than Young Krakatau;2) Anak Krakatau magma storage is deeper (up to 26 km), less differentiated, and erupted hotter but more reduced compared to Old and Young Krakatau. The Old and Young Krakatau lavas chemical characteristics are included at maturation phase (pre-CFE), whereas the Young Krakatau pumice samples were the product of the second CFE. Lastly, the post-second CFE activity of Anak Krakatau is currently in an incubation phase and represented by mafic products. Knowing that the volcano has experienced maturation and CFE phases in the past, the current Anak Krakatau may evolve to those phases in the future.