Numerical Simulations of Volcanic Ash Plume Dispersal from Kelud Volcano in Indonesia on February 13, 2014

In order to evaluate airborne ash densities, a real-time volcanic ash dispersion model, PUFF, is applied to the February 13, 2014 eruption of Kelud volcano in Indonesia. The emission rate of the ash mass from the vent is estimated based on the empirical formulae tested at Sakurajima volcano using ground deformation and seismic monitoring data.According to the result of the PUFF model simulation, the circular shape of the anvil ash cloud 17 km in height extends during the first two hours over a radius of 200 km from the volcano. The core region within 50 km of the volcano shows an airborne ash density of 1000 mg/m3. Three hours after the initial eruption, the area with 100 mg/m$^bm 3$ extends 300 km to the west, covering Yogyakarta Airport. Due to low-level winds, Surabaya Airport to the northeast also becomes part of the area with 100 mg/m3. The result of the ash plume dispersal 7 hours into the eruption indicates that the entire island of Java is in the danger zone for commercial airliners, as ash exceeds 10 mg/m3. Although satellite images show that the ash plume is located only in the southern half of western Java, the simulation results quantitatively indicate much wider extents of the aircraft danger zone.