Rabaul volcan est l'un des volcans les plus actifs et les plus dangereuses en Papouasie-Nouvelle-Guinée. Rabaul a explosé violemment en 1994 et a dévasté la ville animée de Rabaul. Depuis lors, le Tavurvur cône jeunes situé à l'intérieur de la caldeira a été le site d'activité persistante proximité sous forme de strombolien au vulcanienne éruptions de cendres. La caldeira a une forme elliptique (14 x 9 km) et est entouré par une crête abrupte volcaniques de plusieurs centaines de mètres de haut. -> Voir la description complète
Ragang is an active stratovolcano 40 km SE of Marawi city, Mindanao Island, Philippines. It is Mindanao's most active volcanoes and belongs to the Central Mindanao Arc. Most of its historic eruptions were small explosive eruptions from the summit crater.
The volcano has a deep summit crater with a prominent 3 km long lava flow extending to the SE.
The last confirmed eruption of Ragang volcano was in 1873.
(Source: GVP volcano information)
Raikoke is a stratovolcano forming a small barren island in the central Kuriles, Russia. It is located 16 km across the Golovnin Strait from Matua Island.
The volcano is mainly basaltic and has a 700 m wide and 200 m deep crater with steep walls. Raikoko has erupted lava flows all along the eastern side of the island.
A large eruption occurred in 1778 which destoryed the upper third of the island. Another strong eruption was in 1925, which reshaped the crater and altered the coastline of the island.
A new lava dome formed at the base of the large older lava dome of Gunung Ranakahin in 1987 and was named Anak Ranakah (Child of Ranakah). No previous historical eruptions were known from Ranakahin. -> Voir la description complète
Raoul Island volcano is the northernmost, largest and best known of the Kermandec islands NE of New Zealand.
The anvil shaped 10 x 6 km wide island is the top of a large stratovolcano breaching the sea surface. At its submarine base, the volcano measures 35 x 20 km. The volcano has 2 overlapping caldera containing 3 lakes (Blue, Green, and Tui). Historical eruptions have been observed since the 19th century. -> Voir la description complète
Rasshua is a large volcano forming the 6 x 13 km elongated Island of Rasshua in the central Kuriles. Rasshua volcano is truncated by a large caldera whose eastern rim is below sea level. There are 2 young active central cones in the caldera, from where most activity in the recent past has taken place. Historic activity consisted in explosive ash eruptions from the eastern cone, but there are prehistoric lava flows from the western cone that flooded the caldera and reached the coast.
Fumarolic activity continues in the eastern crater and in the saddle between the 2 summit cones. -> Voir la description complète
The Raton-Clayton volcanic field, in the extreme northeastern corner of New Mexico, approximately 125 kilometers east of Taos, comprises Sierra Grande shield volcano and 125 cinder cones and associated lava flows, ranging in age between 1 million to ca. 60,000 years old.
The impressive Capulin National Monument is the probably youngest cinder cone of the field. It is 305 m high and has a base diameter of 1.7 km and has a 125 m deep crater. Argon-argon dating has resulted in an age of Capulin at 56,000 to 62,000 years ago.
The largest volcanic edifice is the large, extinct andesitic Sierra Grande shield volcano, which is 15 km in diameter and 600 m high.
Highway 64 cuts directly through the center of the field and connects the towns of Raton and Clayton.
Rausu volcano (羅臼岳 Rausu-dake) is an active stratovolcano on the Shiretoko Peninsula of NE Hokkaido. It is located on a ridge 5 km SW of Shiretoko-Iwo-san volcano, the NE-most active volcano in Hokkaido.
Rausu's summit contains lava domes. Young lava flows are visible on the NW and SE flanks of the volcano.
There is no known historic eruption, but field evidence shows that the last eruption took place between 1750 and 1850 AD. -> Voir la description complète
Reclus volcano is a stratovolcano located in southern Chile and belongs to the Australandean Volcanic Zone of south Patagonia.
The volcano was first recognized as as a volcano in 1987. It contains a large dacitic cone with a 1 km wide crater.
Reclus Volcano Eruptions -> Voir la description complète
Volcán Resago is a cinder cone with a double crater in Linares province. The volcano produced a basaltic-andesite lava flow that traveled about 3 km to the WNW into Laguna Dial. The youthful cone may have been formed during an undocumented eruption during historical time.
Un type de magma très riche en silice et très visqueux. Les Rhyolites, signifiant (Rhyo: rheîn=couler, lites: lithos=pierre) sont des roches magmatiques éffusives, dont leur équivalent en roche grenue plutonique est le granite. On les rencontre dans la composition de ponce rhyolitique (dans les dépôts de retombées ou dans les ignimbrites), de lave, ou dans l'obsidienne. Le terme Rhyolite est toujours utilisé pour signifier le nom d'une roche volcanique formée par un magma de composition rhyolitique.
Sur le plan textural, c'est une roche riche en verre, à teinte claire, et microlithes (petits cristaux non visibles à l'oeil nu), avec de rares phénocristaux.
Ex: Pantellerite, Obsidienne, Pechstein ou Rétinite, Rhyolitoïde, Dellenite,...
Risco Plateado is a volcanic complex about 10 km south of the Caldera del Atuel and consists of a stratovolcano cut by a 4-km-wide caldera. The age of the last eruption is known but thought to be Holocene (within the past 11,000 years). There are youthful-looking basalt lava flows from the SW rim crater that extend NE to the Rio del Atuel. -> Voir la description complète
Rishiri volcano (利尻山, Rishiri-zan) forms is a small island about 20 kilometers west of the northern tip of Hokkaido. The andesitic stratovolcano last erupted ca. 8500 years ago and is strongly eroded. Erosion has sculptured a sharp-topped summit and steep radial ridges. The latest eruptions of Rishiri volcano was ca. 8-9000 years ago.
Rishiri is part of the Rishiri-Rebun-Sarobetsu National Park. A well-known feature is Rishirifuji Onsen, a thermal spring with indoor and outdoor baths at the southern end of the town of Oshidomari. -> Voir la description complète
Ritter volcano is a very active basaltic-andesitic stratovolcano and forms the Ritter Island between Umboi and Sakar Islands in the Dampier Strait., ca. 9.5 km NE of Umboi Island and 21 km west of New Britain.
Present-day Ritter Island is the remnant of a larger island which was destroyed during a massive flank collapse in 1888, which reduced the near circular steep and 780 m high original volcanic island to to a small 140 m high and 1900 m long arcuate island with a steep west-facing cliff that continues below sea level. Devastating tsunamis were produced by the 1888 collapse and swept onto the coast of Papua New Guinea and offshore islands.
Many eruptions from Ritter Island are submarine. Along with the landslides that often accompany them, they frequently generate tsunamis. -> Voir la description complète
Robledo volcano is a 6-km wide caldera in NW Argentina, located 80 km SW of the much larger and better known Cerro Galán caldera.
It contains Cerro Blanco del Robledo lava dome on the southern rim of the caldera. There are extensive rhyolitic pumice-fall deposits around the dome. Older, but well-preserved pyroclastic-flow deposits underly the lava dome of Cerro Blanco and are exposed on the floor of the caldera and on its NW flanks.
Satellite surveys in the 1990 have shown subsidence of the Robledo caldera.
Romeral volcano, located 16 km SE of the small town of Aranzazu, is the northernmost volcano in South America. The volcano is probably still active. It has produced 2 plinian eruptions about 8460 and 7340 years ago. -> Voir la description complète
Rota (also known as Orota) volcano in Nicaragua is located between the more active Cerro Negro and Telica volcanoes in the central Marrabios Range. It is a symmetrical stratovolcano truncated by a 1 km wide circular crater.
There are no recent eruptions from Rota, and the cone is vegetated, but the volcano is still active.
Seismic swarms occurred at Rota volcano in 1986, 1989, and 1992. -> Voir la description complète
Rudakov volcano is a small isolated stratovolcano in central Urup Island, Kuriles, on the Tokotan Isthmus on the coast of the Sea of Okhotsk.
The small basaltic-andesite volcano contains a 700 m wide crater with a 300 m wide lake.
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