|1564/1565; An eruption occurred at the top of the crater which caused ash rain and lava flow. The sound of the boom was heard up to a distance of approximately 200 km, while the lavanya flow reached the sea. As a result of this eruption caused damage to forests and arable land, it also caused human casualties.
1673, May 20-21; there were eruptions that emitted a lot of ash, until the city of Ternate became pitch black. Clouds of ash are unusually large, until at a distance of +/- 350 km the ash still settles thick enough. Along with this eruption also felt an earthquake. As a result of this eruption also caused damage to forests and arable land and caused human casualties.
1917, October 18; there was an increase in activity, sometimes flashes of light appeared on the side of a puff of thick smoke poles.
1926; There was an increase in activities on June 1 and 2, allegedly an explosive eruption from the central crater. A few days later de Kroon climbed to the top, at night he saw incandescent fire in five solfatara field sites.
1949; There was an increase in activity, it was suspected that there had been an explosive eruption from the central crater.
1950; In October an explosive eruption occurred. As a result of this eruption, plants on the edge of the south-southwest crater were burned, ash was thick enough.
1951, April 12; black smoke came out from the crater. This smoke was seen from Gamsungi village. On 2 May there were 2 rumbling sounds from the crater hole. On July 16 there was a small eruption. This year also the temperature of the crater shows a relatively high temperature which ranges from 400-5000 C.
1983, February 16 and 17; ash eruption. No further information.1987, April 13, 24, 25 and 26; there was an ash eruption, smoke height around 1000 m, moving southward. The eruption material was thrown and fell back around the crater. Some coastal residents evacuated, after Vulcanology officers came to carry out the inspection, only then they returned.
1997, January 10; there was an eruption of ash as high as 200 m above the peak
2007; Activity status of Mount Gamkonora is increased from ACTIVE NORMAL (Level 1) to WASPADA (Level II) On 9 July, at 16:30 WIT, Blowing ash increases to reach 4000 m from the summit of G. Gamkonora.
At 16:30 WIT, the activity status of G. Gamkonora was increased from SIAGA (Level III) to AWAS (Level IV). Local Government and Observers G. Gamkonora have decided for people who live in Disaster Prone Areas II and III or who live within an radius of 8 Km from the center of the eruption (Kp. Baru, Kp. Adu, Kp. Nanas, Kp. Ngawet, Kp. Jere, Gamsungi, Kp. Bataka, Kp. Talaga, Kp. Tobelos, Kp. Gamkonora and Kp. Sarau), to avoid throwing incandescent material and heavy ash rain it was recommended to evacuate to the north (Ibu Tengah district).
July 10 (early morning); Fire rays observed at an altitude of 10-20 m above the peak, accompanied by flares of incandescent material. The eruption accompanied by a boom still occurs with smoke altitude of 2000-4000 m.
2007, July 11-13; There is still an eruption with increasingly weak pressure and smoke height around 100-2500 m 12 and small eruptions still occur.…
|Mount Gamkonora based on the shape of the landscape is divided into 5 morphological units namely; crater morphology, peak cone morphology, slope morphology, foot morphology and terrain morphology (Mulyana, 1995). In the peak area there are 3 main craters, the order of its appearance begins with the formation of crater 1 which has the largest dimension with the northernmost point at the top of Gamkonora mountain, followed by the formation of craters 2 and 3 which are smaller in succession to the south. In the crater 3 the activity of blowing solfatara / fumarola still continues until now .. The three main craters found on the top of Mount Gamkonora show the shape of “rift volcano”.
Based on the source, type and process of formation, the rock constituent of G. Gamkonora is divided into: Crater Product 1, Crater Product 2 and Crater Product 3 (Mulyana, 1995). The composition of Mount Gamkonora lava ranges from andaltite basaltic to andesite. In general, porphyritic lava-lava consists of plagioclase, klinopyroxene, black minerals such as magnetite, sometimes hornblende. The basic mass of plagioclase microlites, volcanic glas, black minerals and little pyroxene. Petrographic features of Gamkonora mountain lava are similar to volcanic lava in Halmahera arc, which is alkaline calk type (Irianto et al., 1993).
The geological structure that develops in Mt.Kamononora and its surroundings is in the form of straightness (volcanic and topographic alignment), fault structures and craters and depression (Mulyana, 1995). All of these local structures are strongly influenced by regional structures and mainly due to the influence of the Sahu depression zone found on Halmahera Island.