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Earth of fire

Actualité volcanique, Article de fond sur étude de volcan, tectonique, récits et photos de voyage

Publié par Bernard Duyck
Publié dans : #Excursions et voyages
Kamchatka Peninsula - location of volcanoes mentioned at the southern tip - doc . KSCNET

Kamchatka Peninsula - location of volcanoes mentioned at the southern tip - doc . KSCNET

The northeast shore of Lake Kuril is dominated by the conical silhouette of the Ilyinsky volcano, nestled in a small depression.

A first volcano was formed to 5,700 BC, on the edge of the NE rim of Lake Kuril caldera.

The modern building was built in a large caldera of 4 km., produced by the collapse of the proto- volcano. Pyroclastic deposits of Ilyinsky overcome the ignimbrite emitted during the eruption of Lake Kuril , showing by their composition that the beginning of the eruption of Ilyinsky follow that which caused the collapse of the caldera Kuril , and a genetic correlation .

After a rest of 1700 years , a major explosive eruption of  VEI 5 took place in 2850 BC. Other eruptions are reported in 2050 BC and 50 AD , producing thick andesitic lava flows , and before a new long rest.

The Kuril lake and the Ilyinsky volcano - photo A.Litsis / photokamchatka

The Kuril lake and the Ilyinsky volcano - photo A.Litsis / photokamchatka

Ilyinsky and thick andesitic flows of more than 200 m. formed in the year 50 - photo Sulerzhitsky LD / KSCNET

Ilyinsky and thick andesitic flows of more than 200 m. formed in the year 50 - photo Sulerzhitsky LD / KSCNET

In 1901, a phreatic eruption formed a maar crater on the eastern flank of the volcano. It is wide of 800 to 1,000 meters , 200 meters deep and breached by a canyon northeast side.

In the foreground, the inner wall of the flank maar of Ilyinski (1901) and Zheltovsky volcano in the background - photo Sulerzhitsky LD / KSCNET

In the foreground, the inner wall of the flank maar of Ilyinski (1901) and Zheltovsky volcano in the background - photo Sulerzhitsky LD / KSCNET

In contrast to the Ilyinsky, the Zheltovsky is a composite building : a large volcanic pedestal is topped by a caldera dated to late Pleistocene . The latter contains a stratovolcano, dated to the late Pleistocene , wearing several extrusive domes formed during the Holocene . The extrusion of domes is related to debris on the slopes of the volcano.

In addition, various explosive eruptions occurred : one , there is 3-4000 years , emitting basalto - andesitic ash ; another around the year 1500 , producing andesitic blocks and ash ; the last in the 19th. century , with fallout of rounded basaltic lapilli rich in inclusions of allivalite and eucrite . Recent eruptions have caused significant lahars , which have reached the Pacific coast.
 

Zheltovsky seen from Vestnik Bay - photo Vera Ponomareva / IVS FEB RAS

Zheltovsky seen from Vestnik Bay - photo Vera Ponomareva / IVS FEB RAS

Sources :

- KSCNET - Kamchatka volcanoes - link

- Global Volcanism Program - Ilyinsky

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