Ashfall analysis of the 2010 Bromo eruption Aisyah Qurrata Aini (a*), Idham Andri Kurniawan (b), Mirzam Abdurrachman (b)
a. Bandung Institute of Technology
Jalan Ganesha 10, Bandung 40132, Indonesia
*aisyahqaini[at]students.itb.ac.id
b. Petrology, volcanolgy, dan geochemistry research group, Bandung Institute of Technology
Jalan Ganesha 10, Bandung 40132, Indonesia
Abstract
Bromo eruption may be dominated by a strombolian eruption, but it still can cause significant damage to the locals and many people around Bromo. For example, the 2010 eruption that lasted for nine months damaged the local economy and shut down three airports in a 250 km radius. Besides that, Bromo is one of the tourist spots at Caldera Tengger Complex, which lead to a more significant risk of eruption hazard. Based on our study, the 2010 eruption has four eruption phases that can be distinguished by stratigraphy and componentry analysis of ash fall deposits around Tengger Caldera. Based on the stratigraphy and componentry analysis, this study evaluates the mechanism of the 2010 eruption. The first phase started with lithic material from the phreatomagmatic eruption. Strombolian activities in the second phase increase the sideromelane component in the sediment. Next, the third phase represents the high percentage of tachylite from the ash explosion. Last, the lithic material rises again in the fourth phase of the eruption. The ashfall dispersion was modeled using TephraProb package performed on MATLAB. Using the wind data from NOAA, the thickness of the ashfall sediment, and other parameters from field observation, this study calculated the probability hazard assessment of the eruption. Ashfall modeling focused on the broadest dispersion of ashfall from phase one.
