Overblog
Suivre ce blog Administration + Créer mon blog

Earth of fire

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

Articles avec #excursions et voyages catégorie

Publié le par Bernard Duyck
Publié dans : #Excursions et voyages

The Unimak island , located in the Aleutian volcanic arc, has at least six volcanoes : the Roundtop , the Isanotski, the Shishaldin, the caldera Fisher, the Progromni group and Faris Peak , all stratovolcanoes , except Westdahl, of a large shield volcano .




 

Map AVO / USGS / Unimak.us - Volcanoes of Unimak Island

Map AVO / USGS / Unimak.us - Volcanoes of Unimak Island

Location of Unimak Island and Shishaldin volcano in the Aleutian arc - doc.AVO

Location of Unimak Island and Shishaldin volcano in the Aleutian arc - doc.AVO

Begin with the Shishaldin, located in the center of the island, because of its current activity. It is listed in aviation code orange by the AVO .

This symmetrical stratovolcano has a basal diameter of 16 km, and rises to 2857 meters, with a small summit crater emitting continuously a little steam . The summit is covered with eternal snow. The northwest flank of Shishaldin, covered with a'a lava, is punctuated by 24 monogenetic cones parasites.

The Shishaldin is dated less than 10,000 years ago and was built on the remains of an ancient somma or a shield, eroded by glaciers, himself on a underbody of volcaniclastic  or plutonic rocks,  age tertiary . Remnants of this ancient building are exposed to the west and north -east to 1500-1800 m in height.



 

Shishaldin - photo Greg Walters / AVO / 05.14.2014 - note the presence of ash on top .

Shishaldin - photo Greg Walters / AVO / 05.14.2014 - note the presence of ash on top .

The Shishaldin and his small permanent plume of steam - 02.09.2008 - photo Bill Springer / Maritime helicopters / AVO

The Shishaldin and his small permanent plume of steam - 02.09.2008 - photo Bill Springer / Maritime helicopters / AVO

A rise in temperature and a minor degassing are now observed ; A photo of May 14 shows traces of fresh ash on top . Seismic stations near the volcano detect short signals of strombolian explosion.

 

Volcano Roundtop - photo Bill Springer / AVO / 2008

Volcano Roundtop - photo Bill Springer / AVO / 2008

At the eastern tip of Unimak , the stratovolcano Roundtop dominates with its 1871 meters a wide valley , 13 km. west of the village of False Pass.

This building, atop eroded and covered with ice and snow, covers the greater part of a large caldera 3 km . which was formed at the beginning of the Holocene. The formation of the caldera produced pyroclastic flows and rhyolitic tephra deposits widely dispersed on the south -western peninsula of Alaska . A group of lava domes was built south of Roundtop .

His only known eruption is dated by the GVP to 7600 BC. In the 1930s , hot springs were found on its slopes .

To follow,  other volcanoes Unimak
.

 

Sources :

- AVO - Volcano information and reports

- Global Volcanism Program - Shishaldin

- Global volcanism Program -

- Unimak Landforms - link

Lire la suite

Publié le par Bernard Duyck
Publié dans : #Excursions et voyages
 Mount Loowit, or mount St. Helens as seen from Elk Rock - photo USGS

Mount Loowit, or mount St. Helens as seen from Elk Rock - photo USGS

Legends of the Cowlitz Indian tribe merge with the history of Mount St. Helens.

The tragic triangle, or " love story of Loowit "

Depending on the version of the Cowlitz ,
Tah-one-lat-clah , "the mountain of fire", was inhabited by an old woman named Loowit . Long before the Europeans arrived , native tribes could cross the Columbia river on dry ground ... when these tribes became greedy and warlike , the Great Coyote took steps that eventually led to the destruction of the bridges. He shut down all domestic fires ... only maintained by Loowit fire continued to burn. His neighbors came in number seeking ways to rekindle their fire. The Great Spirit then asked Loowit what she wanted as a reward for his peaceful sharing. She shyly suggested its rejuvenation and beautification ... so it was done !

Accomplished his transformation , she inadvertently rekindled the fires of war , attracting the attention of two chefs, Pahtoe , ruling the north side of the Columbia river and Wyeast, leader of the Multnomah people south of the river. They fought for the favors of Loowit , destroying villages and forests. The Great Spirit separated the rivals by collapsing the "Bridge of the Gods" in the Columbia (created by the "Bonneville Slide" , a landslide consecutive an earthquake of M9)

According to legend of Cowlitz , the Great Spirit changed the protagonists of this love triangle into mountain : Wyeast became Mount Hood, Pahtoe became Mount adams , while the beautiful Loowit was personified by St. Helens.

(Note that this legend is a little different from that of the tribe Klickitats )

Emblem of the Cowlitz tribe, with St. Helens - doc. Cowlitz tribe

Emblem of the Cowlitz tribe, with St. Helens - doc. Cowlitz tribe

 Map of the ancestral area of ​​the Cowlitz tribe

Map of the ancestral area of ​​the Cowlitz tribe

The Cowlitz tribe :

This small tribe living north of the Columbia river in houses made ​​of wooden planks. At the time of the Lewis and Clark expedition , the Cowlitz were already in decline, which accelerated during the 19th century. An epidemic destroys a large part of the population , leaving only 500 Cowlitz . The population is slowly recovering and now has 1,400 heads  living on their ancestral lands.

It is likely that their language has gone out , or mixed in with the neighbors. They were known for making baskets, decorated with geometric designs, made ​​with bear grass , roots and cedar bark and horse hair, for picking fruits and berries. These baskets often repaired , passed from generation to generation .

The Cowlitz were recognized by the Federal Government only in 2000 , and are held to establish tribal lands in the state of Washington. A large Powwow is held every year to keep alive the tribal traditions.

Powwow of the Cowlitz tribe - photo Holly Pederson / for The Chronicle

Powwow of the Cowlitz tribe - photo Holly Pederson / for The Chronicle

On the left, the tragic triangle formed by three volcanoes - right , legends of the Cowlitz Indian tribe by Roy I. Wilson - click on the image to enlarge.On the left, the tragic triangle formed by three volcanoes - right , legends of the Cowlitz Indian tribe by Roy I. Wilson - click on the image to enlarge.

On the left, the tragic triangle formed by three volcanoes - right , legends of the Cowlitz Indian tribe by Roy I. Wilson - click on the image to enlarge.

The poem "Loowit ":

Fabienne Ginner wrote a little poem entitled "Loowit" . In acrostic, found his other name , St Helens

 

" Loowit " poem by Fabienne G " Volcana " - photo of the author

" Loowit " poem by Fabienne G " Volcana " - photo of the author

Sources:

- Native Culture - Mt St Helens Native American Tribe Folklore - link

Lire la suite

Publié le par Bernard Duyck
Publié dans : #Excursions et voyages
 Topography of the caldera of Bolshoi Semiachik , and his numerous volcanoes and domes

Topography of the caldera of Bolshoi Semiachik , and his numerous volcanoes and domes

Both ends , north and south of the Kronotsky Reserve, are little illustrated.

Located south of the Kronotsky Reserve, the Bolshoi Semiachik Volcanic complex has been built in a large caldera 10 km wide , closed west side, and occupying a volcano- tectonic depression, dated from the late Pleistocene, along the Pacific coast Kamchatka .

The post- caldera volcanism includes lava domes , including Ivanov, the Ezh and Korona , and many stratovolcanoes , certain assets of the Holocene : the volcanoes Zubchatka ( Bolshoi Semiachik ) Zapadny Barany , Vostochny Barany , Zentralny Semiachik , Popkov , Plosky and Burlyashchy are the most important of the complex.

The Bolshoi Semiachik complex view of the wall of the caldera - The Zubchatka is the big building in the background - photo Nikolai Smelov / KSCNET

The Bolshoi Semiachik complex view of the wall of the caldera - The Zubchatka is the big building in the background - photo Nikolai Smelov / KSCNET

The dating of the dome Ivanov was not easy to establish. He did not produce lava flows and is not covered by layer of ash ... however we found a well near the dome, which was identified in, a layer of pumice lapilli andesitic , caught between the tephra of Karymsky - dated 5900 BC - and a layer of ash called "Lower yellow ash" - dated 7500 BC. This allows us to date the dome Ivanov between 6500 and 7000 BC .

Domes Ezh ( Hedgehog ) and Korona (Crown) were produced long lava flows and associated lahars , which allows them dating : to 3600 BC , according to a tehra,marker of the eruption of Avachinsky .

Bolshoi Semiachik - Ezh dome - photo Nikolai Smelov / KSCNET

Bolshoi Semiachik - Ezh dome - photo Nikolai Smelov / KSCNET

The complex has a hydrothermal activity , especially located on the western slopes of the Bolshoi Semiachik and Zentralny Semiachik .

The eastern part of the thermal field Burlyashchy include steam jets , with temperatures up to over 137 ° C. The thermal field of the central Semiachik home the Chernoe lake, a lake emitting vapors.

 

Bolshoi Semiachik thermal field - left,  thermal field Burlyashchy - right on Lake Chernoe - photos KSCNET -  A click to enlarge .Bolshoi Semiachik thermal field - left,  thermal field Burlyashchy - right on Lake Chernoe - photos KSCNET -  A click to enlarge .

Bolshoi Semiachik thermal field - left, thermal field Burlyashchy - right on Lake Chernoe - photos KSCNET - A click to enlarge .

North of Kronotsky Reserve, the Gamchen Volcanic Group forms a volcanic chain oriented North - South , with the massive Gamchen and the cone Barany , the Komarov , and the Vysoky .
 

Volcanic Group Gamchen : From left to right: the four summits of the volcano Gamchen , the yellowish summit of Komarov , composed of hydrothermally altered rocks , and to the extreme right, Vysoky volcano. - Photo Philip Kyle / KSCNET

Volcanic Group Gamchen : From left to right: the four summits of the volcano Gamchen , the yellowish summit of Komarov , composed of hydrothermally altered rocks , and to the extreme right, Vysoky volcano. - Photo Philip Kyle / KSCNET

The massive of Gamchen is a complex of four stratovolcanoes, surmounting a shield. The Severny Gamchen and Yuzhny Gamchen are two eroded Pleistocene stratovolcano . The Molodoi is a small stratovolcano located on the eastern flank of Severny Gamchen . The Barany is located on the south-eastern flank of Yuzhny Gamchen ; wearing a crater of youthful appearance , 500 m.on 200 , its eruptions , dated 1650 and 550 BC , produced a lava field extending NE and E . A young lava dome , the Lukovitsa , formed on the sidewall of Barany , at the end of the period of activity .

Collapses of the complex at the beginning of the Holocene and deposits of debris avalanches formed a field with an hummock topography on the east side of the volcano, called "Moon hills" .


 

In the foreground, the Komarov , followed by summits Gamchen - and at the bottom , right, the silhouette of Kronotsky - KSCNET / Photo Philippe Bourseiller / GVP

In the foreground, the Komarov , followed by summits Gamchen - and at the bottom , right, the silhouette of Kronotsky - KSCNET / Photo Philippe Bourseiller / GVP

The uppermost zone of Komarov , hydrothermally altered - photo Philippe Bourseiller / KSCNET / GVP

The uppermost zone of Komarov , hydrothermally altered - photo Philippe Bourseiller / KSCNET / GVP

The Komarov complex (or Komarova ) is surmounted by an eccentric caldera 4 km on 2.5 . The Vysoky and the Komarov has the same magmatic system, producing an andesite of same composition , and different from that of the volcano Gamchen .

The young cone Komarov , 2070 m high , was built at the western end of the caldera ; he wears  two craters , one on top and one on the upper East side . All the summit region is subjected to extensive hydrothermal alteration , and retains active fumarole , as found on the side N and S.

The Vysoky further north , has been active since the early Holocene until the beginning of our era , while the Komarov began to form there 1500 years. , after stopping activity of Vysoky . Bizarrely , the Vysoky is not included on any list of active volcano.



 

The Vysoky was active until the beginning of our era , with the lava flow dated 2000 years ago - photo Vera Ponomareva / KSCNET

The Vysoky was active until the beginning of our era , with the lava flow dated 2000 years ago - photo Vera Ponomareva / KSCNET

Sources:

- KSCNET - Kamchatka Holocene Volcanoes - link

- Global Volcanism Program -  Komarov

- Global Volcanism Program - Gamchen

- Global Volcanism Program - Bolshoi Semiachik

Lire la suite

Publié le par Bernard Duyck
Publié dans : #Excursions et voyages
 Uzon caldera - the Valley of Geysers - photo Antony Van Eeten 2011

Uzon caldera - the Valley of Geysers - photo Antony Van Eeten 2011

The Valley of Geysers was discovered by chance in April 1941 by a team of hydrologists led by Tatiana Ustinova .

In a study on Shunmaya river, leaving the caldera Uzon , they discovered a passage between the rocks and reached a tributary of the river unknown . Lunch time came , they stopped to eat ... during the break, they were surprised by a sudden jet of water : they came to see a geyser, first seen in Kamchatka . Tatiana baptized " Pervenets ", " the firstborn ." The history of the Valley of geysers had just begun.

The mysterious tributary called Geysernaia ; This river has its source at the foot of the volcano Kikpinich . Its waters are warm ; they do not fall below 19 ° C, even in the midst of winter. About 8 km of its course , there are more than thirty geysers , large or small , hot springs and mud pots . This assembly is heated by this magma deep beneath the caldera Uzon .

 

Uzon caldera - the Valley of Geysers - photo Antony Van Eeten 2011

Uzon caldera - the Valley of Geysers - photo Antony Van Eeten 2011

Uzon caldera - the Valley of Geysers - photo Antony Van Eeten 2011

Uzon caldera - the Valley of Geysers - photo Antony Van Eeten 2011

Uzon caldera - the Valley of Geysers - a hot spring - photo Antony Van Eeten 2011

Uzon caldera - the Valley of Geysers - a hot spring - photo Antony Van Eeten 2011

Uzon caldera - the Valley of Geysers - a pool of bubbling mud - photo Antony Van Eeten 2011

Uzon caldera - the Valley of Geysers - a pool of bubbling mud - photo Antony Van Eeten 2011

These geysers are named : Velikan ( giant ) Zhemchuznhy ( pearl ) Sakharny ( sweet ) Troynoy ( triple ) , Konus ( cone ) , Maly (small ) , Bolshoy (Great ) Shchel ( crack) .

Their manifestation is punctuated over a special and different way : the Velikan occurs 25 m. every 6 hours, the Maly 8 m. every 35 minutes , the Bolshoy 10 m. every 10 minutes ...

Uzon caldera - the Valley of Geysers - Dam on the Geysernaia following the landslide in 2007 - photo I.Shpilenok

Uzon caldera - the Valley of Geysers - Dam on the Geysernaia following the landslide in 2007 - photo I.Shpilenok

This beautiful landscape is subject to the vagaries of the weather: thus, in October 1981 he suffered of the travel of Typhoon Elsa ; Geysernaia the river then went 3 meters , causing damage .

On 3 June 2007 , the valley was partly affected by a landslide that wiped out five geysers : the Pervenets, the Troynoy, the Sakharny, the Sosed and Uvodopa ; he also created a barrier to the natural flow of the Geysernaia river and a dam  who drowned for a time other structures.

Caldera Uzon - The Valley of Geysers - the new geyser " Prikolny " - photo I.Shpilenok 2009

Caldera Uzon - The Valley of Geysers - the new geyser " Prikolny " - photo I.Shpilenok 2009

In 2009 , a new geyser, named " Prikolny " (" Particular " ) : originally a hot spring, the geyser has eruptions every 6 to 20 minutes; it is unique in the sense that it constantly recycles the same water. The water flows at 5 m. height falls in the cavity to emerge periodically.

 

Sources :

- Global Volcanism Program - Uzon - Montly reports  

- Le glissement de terrain 2007 - Spanishflyer livejournal  

- The valley of geyser - Kamchatka geysers

Lire la suite

Publié le par Bernard Duyck
Publié dans : #Excursions et voyages
 Kronotsky volcano overlooking the reserve of the same name - photo Russian traveling

Kronotsky volcano overlooking the reserve of the same name - photo Russian traveling

Lighthouse of the Kronotsky Reserve, the symmetrical stratovolcano Kronotsky is located between the Pacific Ocean and the largest lake in Kamchatka .

Above 3528 meters, it is cut by deep radial valleys of more than 200 meters. He wears a summit glacier , including lobes down to 900 meters. It is essentially of basaltic composition , except for a  basalto-andesitic neck, which forms a plug in the summit crater , and a flank lava flow .

Cinder cones dot the flanks.

Small phreatic eruptions have been reported by hunters in 1922 and 1923 , confirmed by the GVP , and followed by fumarolic activity.

The Kronotsky seen from the Krasheninnikov caldera - photo I.Shpilenok

The Kronotsky seen from the Krasheninnikov caldera - photo I.Shpilenok

To the center, bordering the Pacific, the symmetric Kronotsky volcano and the lake of the same name , and left the Krasheninnikov - photo Nasa / ISS Expedition 25 crew

To the center, bordering the Pacific, the symmetric Kronotsky volcano and the lake of the same name , and left the Krasheninnikov - photo Nasa / ISS Expedition 25 crew

The lake Kronotsky owes its formation , between the late Pleistocene and the early Holocene , to dams formed on the river Listvenichnaya by lava flows on the south side of the volcano Kronotsky .

This lake has an area of ​​242 km ² and a catchment area of ​​330 km ² , making it the largest lake in Kamchatka . It also has an impressive population of nerkas , with 30 million of these sockeye.

In the eastern part of the lake, there hare 11 islands,  thirty meters above the level, some of which are home to hundreds of nesting pairs of Pacific Herring . Osprey and Steller eagles nest in larch surrounding the lake.

The volcano Kikhpinych - in the foreground , the cone Savich and recent lava flows . - Photo I.Shpilenok

The volcano Kikhpinych - in the foreground , the cone Savich and recent lava flows . - Photo I.Shpilenok

The volcano Kikhpinych is the collective name for several structures of different age.

Three structures are formed on an east-west oriented ridge :
- The Zapadnyi ( "West" ) was built between 2200 and 2100 BC ( radiocarbon ) .
- The cone Savich , 1552 m , began to form there 1450 years
- And the lava dome Crab and its lava flows , there a few hundred years on the eastern flank of Savich .

These structures Holocene accompanied the ruins of the Old Kikhpinich or Mt Peak, dating from the Middle Pleistocene , and to the south of Mt Zheltaya (" Yellow ") , dating from the late Pleistocene .

 

Sources :

- KSCNET - Kamchatka Holocene volcanoes - link

- Global Volcanism Program - Kronotsky

- Global Volcanism Program - Kikhpinych

Lire la suite

Publié le par Bernard Duyck
Publié dans : #Excursions et voyages
Kronotsky Reserve : left, Kronotsky volcano , on the right Krasheninnikov . - Photo Vera Ponomareva / KSCNET

Kronotsky Reserve : left, Kronotsky volcano , on the right Krasheninnikov . - Photo Vera Ponomareva / KSCNET


Somewhat forgotten among the stars of the Kronotsky reserve, the Krasheninnikov volcano is a hybrid consisting of two overlapping stratovolcanoes , and are built in a caldera of Pleistocene 9 of 11 km.

A series of dykes oriented north-south , parallel to the eastern volcanic field , in conjunction with an area of expansion in sub-surface , cut the edge of the caldera towards the Maly semiachik , crossing passing the caldera Uzon , and Bolshoi Semiachik . These dykes have fueled the monogenetic vents in the northern zone , extending over 15-20 km beyond the caldera.

Aerial views reveal its inner beauty, and two large craters 800 meters.

Volcanoes of the Kronotsky Reserve

Volcanoes of the Kronotsky Reserve

The summits of Krasheninnikov , with in the background, the volcano Kikhpinych - photo Michael Melford / National Geographic

The summits of Krasheninnikov , with in the background, the volcano Kikhpinych - photo Michael Melford / National Geographic

White pumice tuff of the Pleistocene caldera (beyond the edge NW of Krasheninnikov ) is surmounted by glacial deposits (clear brown) and pyroclastic deposits and soil dated from Holocene (dark brown). - Photo Andrei Nechaev / KSCNET

White pumice tuff of the Pleistocene caldera (beyond the edge NW of Krasheninnikov ) is surmounted by glacial deposits (clear brown) and pyroclastic deposits and soil dated from Holocene (dark brown). - Photo Andrei Nechaev / KSCNET

The Southern Cone was built first, from 8050 BC ; its last eruption, to 5450 BC, was followed by a period of rest in the caldera of 900 years.

Then the activity has moved two kilometers further north, and the northern cone construction began on the slopes of the old cone to 4,450 BC, the magma having found an easier path through the newly formed dykes rather than using the old conduit.

Northern cone is topped by a caldera containing a small stratovolcano, whose crater contains a small cone ... in the manner of matryoshka . The last eruption of Krasheninnikov occured there are only 460 years , with the formation of small lava cone Paul in the North summit crater cone, and a lava flow from a vent located on the upper side southwest of the Southern Cone .

The Krasheninnikov , with in the background , the perfect silhouette of Kronotsky - photo E.Shpilenok / live newspaper

The Krasheninnikov , with in the background , the perfect silhouette of Kronotsky - photo E.Shpilenok / live newspaper

Southern cone of Krasheninnikov , containing the small cone Paul - photo E.Shpilenok / Wildlife Photo Russia

Southern cone of Krasheninnikov , containing the small cone Paul - photo E.Shpilenok / Wildlife Photo Russia

The volcano is named after Stepan Petrovich Krasheninnikov (1711-1755) , Russian explorer, naturalist and geographer, who made the first full description of Kamchatka in the early 18th century.

 

Sources :

- KSCNET - Kamchatka Holocene Volcanoes - link

- Global Volcanism Program - Krasheninnikov

Lire la suite

Publié le par Bernard Duyck
Publié dans : #Excursions et voyages

Located as the Kurile Lake in the Pauzhetka caldera, dated 443,000 years , the complex of domes Diky Greben covers more than 60 km ².

The complex consists of Mont Nepriyatnaya - "Unpleasant " , the main dome , many flanks domes , their lavas and pyroclastic flows ; it is the largest extrusive block of the Kamchatka - Kurile arc .

 

The Diky Greben complex , Mt Nepriyatnaya , its N & S flows, and , in the background , the Kuril Lake - / KSCNET Photo Nikolai Smelov

The Diky Greben complex , Mt Nepriyatnaya , its N & S flows, and , in the background , the Kuril Lake - / KSCNET Photo Nikolai Smelov

The complex is formed during three short periods of activity separated by long rest periods of about 3,000 years each.

- His life begins to 5700-5600 BC, after the collapse of the caldera of Lake Kuril .

- The second phase takes place between 3500 and 2250 BC.

- The greater part of the complex, including lava north and south of Mt Nepriyatnaya , was formed during an eruption in the year 350 : on the north of the latter, a thick lava flow lined with well expressed levees, and south, a topography that marks its origins in a sector collapse of the main lava dome. A total of 9-10 km ³ of dacite and 2-3 km ³ of andesite was issued at that time.

Two large craters and some smaller vents were formed thereafter.

During these three phases , deformation and landslides occurred , some constituting dams on the Ozernaia River, the drainage of Lake Kuril .

Diky Greben - Mt Nepriyatnaya and his flows - Landsat 7 image of Dikii Greben ' volcano draped over a digital elevation model . Processed by Dmitry Melnikov .

Diky Greben - Mt Nepriyatnaya and his flows - Landsat 7 image of Dikii Greben ' volcano draped over a digital elevation model . Processed by Dmitry Melnikov .

The Kambalny , located south of the volcano -tectonic depression Pauzhetka is the major stratovolcano the southernmost of the peninsula of Kamchatka .

Peaking at 2156 meters, it consists of two cones : in the west, a cone formed there about 6,300 years , was destroyed by a large collapse 6,000 years ago ( radiocarbon ), which has generated at least three avalanches debris , estimated between 5 and 10 km ³ of total volume.

 

The Kambalny - photo Igor Shpilenok / live newspaper

The Kambalny - photo Igor Shpilenok / live newspaper

The first avalanche traveled 14 km south-easterly direction . A new cone is then formed in the crater , following strong explosive eruptions . Another collapse involved as the former cone cone as the new emerging cone, forming a deposit of 20 km long and 5 wide, to the SSO of the volcano. The third debris avalanche , which traveled more than 10 km NE, is dominated by hydrothermally altered rocks of the former ridge.

Subsequent eruptions have built the new cone, that filled a part of the collapsed crater, forming an asymmetric structure. The present crater is 800 meters wide by 400, and 150 m deep . Five cinder cones dot the flanks of the volcano .

The clearance between the hummocks of the debris avalanches deposits is now occupied by peatlands , which protected all the thin layers of ash from the volcanoes of South-Kamchatka and history.

The last major eruption of Kambalny date of 1350 ; the phreatic eruption left debris on the southwest slopes of the volcano . Subsequent smaller eruptions have produced lahars .


 

Kambalny - area avalanche hummock swamp - photo LD Shulerzhitsky

Kambalny - area avalanche hummock swamp - photo LD Shulerzhitsky

Its current activity is confirmed by the presence of zones of fumaroles , hot springs and mud pots in nine areas concentrated on the dorsal Kambalny dominant the tundra of 800-1000 meters.
 

Hydrothermal field near Black Cliffs / Kambalny volcano - photo I.Shpilenok / Kronoki.ru

Hydrothermal field near Black Cliffs / Kambalny volcano - photo I.Shpilenok / Kronoki.ru

Hydrothermal field near Black Cliffs / Kambalny volcano - photo I.Shpilenok / Kronoki.ru

Hydrothermal field near Black Cliffs / Kambalny volcano - photo I.Shpilenok / Kronoki.ru

Sources :

- KSCNET - Holocene Kamchaka volcanoes - link

- Global Volcanism Program - Diky Greben

- Gloval Volcanism Program - Kambalny

Lire la suite

Publié le 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

Lire la suite

Publié le par Bernard Duyck
Publié dans : #Excursions et voyages

The extreme southern tip of the Kamchatka Peninsula , although less visited, has a set of interesting volcanic structures.

Among these , the Kuril Lake , discovered in 1703 by the Cossacks .

It is located in the eastern part of the caldera Pauzhetka , extending east- west for 25 km ; it is intersected by a major fault system .

The Kuril lake, 13 km by 10 , has an irregular bottom; its northern part shaped plate gravy boat has a maximum depth of 300 meters , while the more irregular southern part , is even more profound. The lake is fed by snowmelt and rainwater , as well as some rivers, Etimynk , Hakytsin , Vychenkiya and Kirushutk . It drains into the Ozernaya River, which flows westward into the Sea of ​​Okhotsk.

Kuril lake / Kamchatka - photo Shine Phantom

Kuril lake / Kamchatka - photo Shine Phantom

Southern Kamchatka : the Kuril Lake

Southern Kamchatka : the Kuril Lake

Kurile Lake caldera was formed in two steps, one dated to the late Pleistocene , 41,500 years ago ( radiocarbon dating ) .

The second step , dated 6440 BC, is considered one of the largest eruptions of the Holocene , ranked VEI 7 by the GVP , the order of magnitude of those of Santorini or Tambora . A total of 140 - 170 km ³ of material was ejected , and pyroclastic deposits have cleared the whole country . Ash from the eruption have been found in more than 1,000 km. on the Asian continent.

The lake has several islands , named Chayachy , Serdtze , Nizkii , Glinyanii and Samang . Serdtze Alaida, in the center of the lake, is a rhyodacitic lava dome with steep walls , which was formed at the end of the caldera -forming eruption .

Several bays were formed by lava flows , the Tioploï Bay has hot springs where the temperature reaches 45 ° C.

Kuril Lake - Salang island - photo Shine Phantom

Kuril Lake - Salang island - photo Shine Phantom

Kuril Lake - the dome Serdtze Alaida and the volcano Ilyinsky - photo Shpilenok / Live Journal

Kuril Lake - the dome Serdtze Alaida and the volcano Ilyinsky - photo Shpilenok / Live Journal

Pyroclastic deposits in the valley of the river Ozernaya , 4 km . west of Lake Kuril , reach a thickness of 100 meters. The erosion of the non-welded ignimbrites formed the famous obelisks of Kutkhiny Baty .

According to local legend , they resemble to giant canoes stood up to dry :
Kutkhu, god and creator of Kamchatka, would have used for fishing on the lake and the close ocean . Before leaving the Kamchatka Kutkhu raised its boats ( Baty ) ... since this place is considered sacred by local tribes .

Kutkhiny Baty - photo Air Pano

Kutkhiny Baty - photo Air Pano

 Kutkhiny Baty - Photo Atlas of wonders

Kutkhiny Baty - Photo Atlas of wonders

 Kutkhiny Baty - photo Igor Shpilenok 2012

Kutkhiny Baty - photo Igor Shpilenok 2012

The Kuril Lake is famous for being the greatest place in Asia spawning kokanee red salmon or alternatively , sockeye . Between 3 and 5 million salmon spawn in the lake between July and March. This attendance is the happiness of brown bears, about 200 individuals, river otters and foxes , supported by Steller eagles ( estimated at between 300-700 individuals population), white-tailed eagles (150-200 ) and golden eagles (50). The lake is also the place of wintering for the whooper swans and ducks (1 500-2 000 ) .

Nearby, the volcanoes Ilyinsky , Kambalny , Koshelev and Zhelotovsky ... to see soon.

 

Sources :

- La caldeira Pauzhetka - Oregonstate University - link

- Global Volcanism Program - Kuril lake

- Les photographes du Lac Kourile. Sergey Gorchkov. - link

Lire la suite

Publié le par Bernard Duyck
Publié dans : #Excursions et voyages
Lassen Volcanic Park - Manzanita Lake - photo Russell Virgilio / NPS

Lassen Volcanic Park - Manzanita Lake - photo Russell Virgilio / NPS

Native peoples :

The vicinity of Lassen Peak have been a meeting point for at least four groups of Indians : the Atsugewi living north and east in the Hat Creek drainage or around Eagle lake . The Maidu lived in a large area south-east, while the Yahi occupied the valleys of Mill Creek and Deer Creek to the south. The Yana have lived in Battle Creek southwest of Lassen Peak.

These tribes had seasonal migrations , according to the movements of their prey and weather conditions: in the summer they hunted and gathered in the highlands ... deer, bison , bear, salmon , nuts and berries were on the menu . In autumn, they moved to the lowlands to cultivate , before settling for the winter in semi-permanent villages at an altitude where it was not snowing . While retaining their own territories, these tribes traded, intermarried, and share the same resources. In the 18th century, these tribes had several thousands of their people ... indivdus regressed after contact with Euro-Americans, even going for the Yahi, fewer originally, to extinction.

 To the left, Maidu Indian / Native Americans of California - to the right, Indian territories / Siskiyous.edu - click on photos to enlarge. To the left, Maidu Indian / Native Americans of California - to the right, Indian territories / Siskiyous.edu - click on photos to enlarge.

To the left, Maidu Indian / Native Americans of California - to the right, Indian territories / Siskiyous.edu - click on photos to enlarge.

Emigrants and settlers :

A first evidence of travel through the region dates back to 1828. Rush to Gold in California brought the first settlers. Two migration routes were developed by William Nobles and Peter Lassen, from 1850. Mining , energy projects development , animal husbandry, and woodwork have all been tried . The beginning of a federal protection has saved the region from an heavy exploitation.

 

Left, the California trail ( red) - the " Lassen cutt -off" in fine lines - right , Peter Lassen / Photo Sierra college edu - . Clicking on the image to enlargeLeft, the California trail ( red) - the " Lassen cutt -off" in fine lines - right , Peter Lassen / Photo Sierra college edu - . Clicking on the image to enlarge

Left, the California trail ( red) - the " Lassen cutt -off" in fine lines - right , Peter Lassen / Photo Sierra college edu - . Clicking on the image to enlarge

Tourism and birth of the National Park :

In the 19th century , there are the beginnings of tourism activities related to fishing , hunting, and an interest in geothermal areas.

Between 1904 and 1907 , a road permit the cars access to this remote valleys. In 1905 , President Roosevelt established the " Lassen Peak Forest Reserve " ... the eruption of 1914-1917 mobilized the attention of Americans and put away the obstacles to the establishment of a National Park.

The Lassen Volcanic National Park is " born of fire " !

The eruption of Lassen Peak was documented by many amateur and professional photographers ...  Benjamin Franklin Loomis photos, particularly of quality , illustrated the eruptions and helped to establish the National Park.

The Loomis Museum houses his photographs , equipment and other artifacts of Atsugewi tribe.

Explanatory plaque of Lassen Volcanic Park - " May 19, 1915 , a night to remember "- photo Loomis / NPS

Explanatory plaque of Lassen Volcanic Park - " May 19, 1915 , a night to remember "- photo Loomis / NPS

The Loomis Museum in Lassen VP - photo Loomis museum

The Loomis Museum in Lassen VP - photo Loomis museum

Left, Pictorial history of the Lassen Volcano by BFLoomis - right , Lassen Peak photo by Loomis / Doc. University of California - click on image to enlargeLeft, Pictorial history of the Lassen Volcano by BFLoomis - right , Lassen Peak photo by Loomis / Doc. University of California - click on image to enlarge

Left, Pictorial history of the Lassen Volcano by BFLoomis - right , Lassen Peak photo by Loomis / Doc. University of California - click on image to enlarge

Sources :

- The Nevada Observer - The Lassen Trail - link

- Lassen County Historic Trails - link

- US Departement of the Interior - Applegate Lassen Emigrant trail

- Lassen vocanic National Park – NPS  - link

Lire la suite

<< < 1 2 3 4 5 6 7 8 9 10 > >>

Articles récents

Hébergé par Overblog