VOLCANOSTRATIGRAPHY OF ANAK KRAKATAU VOLCANIC COMPLEX AND COMPARISON BETWEEN ANAK KRAKATAU ERUPTION IN 2018 AND KRAKATAU ERUPTION IN 1883

• Main Author: Rahaldi Taher, Muhammad
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/70342
• Institution: Institut Teknologi Bandung

In December 2018, Anak Krakatau Volcano located in the Sunda Strait has landslide, eruption, and tsunami that changed the geological setting of the Anak Krakatau Volcanic Complex. The eruption that occurred in December 2018 is compared to the violent eruption of Krakatau in 1883. This research uses literature study, remote sensing, and geological mapping to determine the latest geological setting of the Anak Krakatau Volcanic Complex which includes geomorphology, volcanostratigraphy, and geological structures and to compare the eruption processes between Krakatau eruption in 1883 and Anak Krakatau eruption in 2018. The study area consisted of five geomorphological units, Panjang Island Caldera Wall Ridge Unit, Sertung Island Caldera Wall Ridge Unit, Rakata Volcanic Remnant Unit, Anak Krakatau Volcanic Cone Unit, and Anak Krakatau Eruption Crater Plain Unit. Volcanostratigraphy of the study area consists of three crown (Old Krakatau Crown, Young Krakatau Crown, and Anak Krakatau Crown) in which there are five hummock (Rakata Hummock, Danan Hummock, Perbuatan Hummock, East Anak Krakatau Hummock, and West Anak Krakatau Hummock ) and 12 mapped rock / deposited units. The primary geological structures found are sheeting joint, autobreccia, jigsaw fit, vesicular, parallel lamination, cross lamination, normal and reverse graded bedding while secondary geological structures were Krakatau Fault and normal fault. Analysist of Krakatau 1883 eruption deposits shows that the eruption stage consist of the Phreatomagmatic, the Sub-Plinian, and the Plinian Stages while the Anak Krakatau eruption in 2018 consist of the Strombolian and the Phreatomagmatic Stage. The geological history of the study area consists of the Pre-Krakatau Period, the Krakatau Volcano Formation Period, the Young Krakatau Caldera Formation Period, and the Anak Krakatau Volcano Formation Period.