PVMBG reported that during 1-12 May seismicity at Ruang was characterized by decreasing numbers of volcanic earthquakes and continuous tremor with decreasing amplitudes. During 8-13 May white plumes rose 200-400 m above the summit and drifted in multiple directions. The Alert Level was lowered to 3 (the second highest level on a scale of 1-4) and the public was warned to stay 4 km away from the active crater.

Geological Summary. Ruang volcano is the southernmost volcano in the Sangihe Island arc, north of Sulawesi Island; it is not the better known Raung volcano on Java. The 4 x 5 km island volcano is across a narrow strait SW of the larger Tagulandang Island. The summit contains a crater partially filled by a lava dome initially emplaced in 1904. Explosive eruptions recorded since 1808 have often been accompanied by lava dome formation and pyroclastic flows that have damaged inhabited areas.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)