Merapi observed gravity anomaly changes in 2019

Volcano disasters are one of the natural disasters that often occur in Indonesia, one of which is Merapi. The impact of the periodic eruption of Mount Merapi is a major threat to the safety of the population periodically. The large eruption cycle of Merapi Volcano occurred in 1587, 1672, 1768, 1822, 1849, 1872, 1930, 1961 and 2010. The results of the 1988,1998 and 2011 studies showed the increasing number of magmas which can be observed from the dimensions of the magma chamber. The structure changes are predicted from phreatic eruptions in 2013, 2014 and 2016, whereas in 2018 and 2019 occurrence of pyroclastic flow. The research of gravity changes used observed gravity anomaly in 2019 as the first step of time-lapse Merapi activity analysis. The number of observation points was 100 with reference to the same position in 2011. The results of observed gravity anomaly changes are increasing mass in the summit area and decreasing mass in the southeast, west and the north of research areas on the elevation of 500 m to 1400 m.