The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported an increase in seismicity at Gede on 1 April. During March plumes (likely steam) rose 50-100 m above the rim of Wadon Crater and an average of 0-1 daily deep volcanic earthquakes were detected by the seismic network. The network recorded 47 deep volcanic earthquakes on 1 April. Seismicity decreased the next day, and no deep volcanic earthquakes were detected during 2-6 April. Plumes continued to rise as high as 100 m above the crater rim. One tornillo earthquake was recorded on 6 April. According to a news article the Balai Besar Taman Nasional Gunung Gede Pangrango (TNGGP) (the Gede national park) had already closed the volcano to climbers months before for unstated reasons and was scheduled to reopen on 3 April; the closure was extended to 7 April as a precaution due to the increased seismicity. The Alert Level remained at 1 (on a scale of 1-4) and the public was warned to stay 600 m away from Wadon Crater. The last eruption occurred in 1957 at Ratu Crater.

Geological Summary. Gede volcano on the NW tip of Java is of Quaternary age and is located about 280 km from the trench (van Bemmelen 1949b). The Gede Salak volcanic complex consists of pyroclastic flows on its western flanks and lava flows on its eastern flanks (Kurniawan et al., 2011). Mt. Gede is also surrounded by Plio-Quaternary tuffs (Banten Tuffs) ranging from 0.07 to 0.1 Ma in age (Pramumijoyo and Sebrier, 1991). Kurniawan et al. (2011) suggest that these Tuffs came from the calderas of the nearby Rawa Dano volcanic complex but gravity anomalies in the region suggest that neither Gede nor its nearby volcanoes could have been responsible for these ignimbrites and instead suggest a pre-existing caldera in the Sunda Straight was responsible (Nishimura et al., 1986).

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Antara News