About the Geopark
Kutralcura Geopark located in the Araucanía region , aims to contribute to social , cultural and economic development of the territory , coinciding with the communes of Melipeuco , Vilcún , Caracautin and Lonquimay .
It is expected that the Geopark Kitralcura achieve the objective of improving the quality of life of its inhabitants, contributes to the dissemination of Earth science at local, regional and national levels , and consequently encourage the establishment of new Geoparks in the country. In this territory , the active volcanoes are a major tourist attraction , and considering its very active, need for local communities and visitors are well informed about the associated risks , and mitigation and emergency response to potential outbreaks.
The creation of this first Geopark in Chile, is an initiative developed by the National Service of Geology and Mining ( SERNAGEOMIN ) , in partnership with the National Forestry Corporation (CONAF ), the Regional Government of the Araucanía , Chile Innova Development Corporation of Production ( CORFO ), the National Tourism Service ( SERNATUR ) , National Corporation for the Environment ( CONAMA ), the Group Nuke Mapu mountain , and the municipalities of Melipeuco , Vilcún , Caracautin and Lonquimay .
This territory , with six protected areas , is within the area of the Biosphere Reserve Araucaria , an area renowned for its biodiversity significance worldwide . The establishment of the Geopark aims also highlight notable geological features of mainly volcanic origin , tectonic and glacial , which highlights the Llaima , Sierra Nevada, Lonquimay , Nevados de Sollipulli Tolhuaca and volcanoes.
The eastern boundary of the Geopark Kitralcura matches the border with Argentina , north borders the Bio Bio Region , and to the west and south, with various municipalities.
The Llaima volcano is one of the most voluminous volcanoes in the volcanic area of the southern Andes of between 37-46 ° S. The conical volcano comprises the main building of 3,125 m asl, highlighting some 1,200 m above the surrounding peaks. The total height of the volcano can be estimated at about 2,400 m above its base, irregular topography, with an average of about 740 meters.
The main building consists of two peaks , the most prominent is the North (3,125 m) , separated by a saddle or portezuelo 1 km in length from south or Pichillaima top of 2,920 m asl. While most exhibits an open summit crater about 350 m in diameter and with a remarkable active fumarole , the south summit presents remains of a smaller cone greater slag nested in another , both open to the southeast due to a landslide . There too weak fumaroles occur .
The western, southwestern and eastern flanks are glaciers, the largest being the western and southwestern with an area of about 19 km2. The eastern flank shows four languages covering a total area of about 10 km2 . Ice has a thick pyroclastic coverage, particularly to the east. This cover has acted as a thermal insulator of glaciers, decreasing the rate of ablation. During the rainy season between June and September , an extensive blanket of snow covers about 1,000 m elevation .
The radial drainage Llaima volcano is represented mainly by the upper basins of the Captrén , Quepe rivers and partly the river Allipén by several rivers and streams, including the stands with his rosary Trufultruful Green Lakes , Rainbow and Conguillío all dammed lavas of different ages. The first two rivers are in turn , tributaries of the soldering iron .
The Llaima a compound stratovolcano , consisting of a mixed and shield volcano , located in the Central Volcanic Zone ( CVZ : 37-42 ° S ) in the Andes of South .
Indeed , comprises a basal structure shaped shield volcano and is surrounded by about 40 adventitious slag cones oriented in a northeasterly direction along a curve alignment of 29 km in length, from the southwest to the northeast of the volcano.
Its lavas spills have been issued within 30 km from the top , enclosing an irregular area of about 700 km2 and reaches a volume of 400 km3
The base of the volcano compound has an elliptical shape whose major axis direction reaches 30 km NS and EW minor axis , is about 25 km.
Llaima volcano activity has developed during the Upper Pleistocene and Holocene. Products issued rests in discordance essentially on tertiary granitoids and Pleistocene volcanic complexes Hirrampe - Melo and
Sierra Nevada . The onset of volcanic activity is uncertain, although the oldest sequence shows the erosive effects of the last glaciation. This suggests that the early products would have been generated after the penultimate glaciation, ie have a maximum age of about 250,000 years , ie Middle to Late Pleistocene .
Whereas morphostructural , stratigraphic , lithological and geochemical criteria have been recognized three evolutionary units : an older unit , another fissure unit and building or principal volcanic cone , plus sequences of pyroclastic deposits .
Immediately in the early postglacial lavas from the old drive , an extensive deposit of basaltic - andesitic pyroclastic flow that ushered in the fissure unit available . This deposit contains remains of charred wood from about 13,200 AP , according to C14 dating method . Considering the sheer volume of this deposit , it is likely that a boiler has been generated as a result of a collapse of the volcanic edifice .
Petrography and Geochemistry
The Llaima volcano consists mainly of basaltic lavas and pyroclastics of andesitic - basaltic whose silica content varying between 50 and 58 % SiO2 , but a deposit of pumice associated with a Plinian eruption , has a dacitic composition ( 65 % SiO2) . The rocks are porphyritic with plagioclase , olivine and clinopyroxene . The geochemical characteristics of Llaima are very similar to other volcanic centers of the southern Andes , as Antuco , Villarrica and Osorno.
The volcanism is generated when the magma reaches and emerges on the surface of the earth. This magma is silicate melt at temperatures between 900 ° and 1400 ° C and has three sentences : A silicate liquid , another solid ( crystals ) and another gaseous . His rise is caused by density differences through fractures in the crust. It occurs in three environments : Underwater Volcanic Chains , Bows and Volcanic Hot Spots . The eruptive behavior is very different and depends on the composition of the magma, among other variables. The best known are the product of volcanism lavas. These vary widely in their morphology , surface features , size and volume , depending on the viscosity grade and silica content .
Products of a volcanic eruption
The effects of lavas depend on the speed , emission rate , volume, and morphology outstanding environment. Temperatures range from 1,300 to 900 ° C. The highest recorded speed reached 70 km / h , but they are very rare cases. In Chile volcanoes , average speeds range between 1 and 10 km / h up to 1 km / day. Their volume can reach 200 million m3 . A surface covered by lava becomes unusable for centuries.
Ejection of pyroclastic
The larger particles ( pumps and blocks ) some of several tons , are cast as a ballistic trajectory and they fall in areas closest to the volcano . The finer material ( ash and lapilli ) form a column (with gas ) , which can reach tens of kilometers. This is scattered by the wind and generates a pen whose propagation depends on the action and wind speed . Some eruptions fine particulate material injected into the stratosphere . Pyroclastic falls can cover areas of hundreds to thousands of square kilometers with varying thicknesses. His initial impact is disastrous , but depending on the material composition and weather conditions , in less than a year may turn into fertile soil .
Volcanic activity variables yields volumes of different gases. The most abundant water vapor, although other toxic such as CO , CO2 , SO2 , H2S, HCl , HF . The composition and volume of volcanic gases emitted is of great importance because of its direct effect on human Greet and the ecosystem in general.
Are real Hurricanes incandescent ( " burning clouds " ) , composed of gases and rock fragments . They are produced by the gravitational collapse of an eruption column because of its high density and are distributed around the volcano , generally radially. Their speeds vary from 100 to 500 km / h , with minimum temperatures of 400 ° C and 10,000 m3 volume of 5,000 km3. They are able to char or burn all organic matter in their path . It also has the ability to trace and high topographic beat. Is the worst volcanic hazard known for its violence, and high temperature range ( eg , even the active volcano Vesuvius erupting 79 AD and the destruction of Pompeii and Herculaneum ) .
Many eruptions are predicted and accompanied by earthquakes of various magnitudes and intensities. Sometimes , they can occur up to 100 earthquakes per day with average intensities. These earthquakes are local, but can be very destructive and violent , but generally do not affect an area of more than 50 km radius .
During some large-scale volcanic eruptions can produce landslides tops and / or flanks of volcanoes , particularly those with large cracks or tears , and other conditions of instability. These debris slides can be hot or cold and have very different sizes, from 0.1 km3 to 30 km3.
Lahar is an Indonesian term coined to refer to debris flows that form in a volcano. Lahars are formed by alluvial water transport as a main component , and rock fragments , ash , ice and logs originating from the slope of the volcano . The average speed of a lahar ranging from 20 to 80 km / h and the tank leaves behind is a fifth of the height of the wave. The volumes vary, generally between 10,000 and 100,000,000 m3 . In the case of Chile, the majority of historic lahars were caused by the sudden melting of snow and ice cover , due to contact with lava flows and pyroclastic flows of small volume . Consequently , the date of an eruption , ie , if it occurs in late winter or summer takes place is very important. In Chile, lahars are the most common hazard and also causes the most damage and human losses.
Its name comes from the Mapudungun means " ditches or blood veins ." At the time of conquest was called Aliante or Imperial . Its last eruptions were moderate to high explosive with a Volcanic Explosive Index ( IEV ) of 1-4 (see types of eruptions) .
Between 1640 , the year of the first documented eruption for Llaima volcano, and 2008 , the year of its last eruption , there have been 48 cases . According to geological field data and the collected history , eruptions of greater magnitude, importance or notoriety , were those of 1640 , 1751 , 1780 , 1790 , 1875 , 1903 , 1927 cycles from 1944 to 1946 and 1955 - 1957 . The most recent and very similar to each other, are the 1979 , 1984, 1994 , and 2008.
Llaima volcano monitoring
The Llaima volcano is monitored through three seismic stations located : 1.150 m and 9.5 km S of the main crater (station Llai ) located at another police checkpoint in Melipeuco (local station MELI ) , 17.5 km the main crater , and a third located in Araucaria Ski Center . The signal of the last two recepciona Volcano Observatory in South Los Andes ( OVDAS ) Sernageomin .
In the area of the Geopark Kitralcura , SERNAGEOMIN publishes hazard map Llaima volcano , which shows the areas that could be affected by different volcanic products associated with any future eruptions. There is also a map of the dangers of volcanoes Bíobío Alto , which includes Lonquimay Tolhuaca and volcanoes.
Early warning is defined as the delivery of timely and effective information , through specialized institutions , enabling communities exposed to danger , take action to avoid or reduce their risk and be prepared for an effective response.
Alert levels are based on three processes:
Prior knowledge and risk management
Monitoring and forecasting of eminent events
Process and disseminating understandable warnings to the authorities and the community
The " Volcanic Traffic Alerts " indicates the alert type and is based on: observed signals and the expected volcanic activity, time available before an eruption , and recommendations to follow during the alert and alarm
Three levels : Green, Yellow, Red
For each level of alert conditions are defined as follows :
Green Alert . The activity of the volcano is from zero to weak explosions with permanent vents , cracks in the glaciers of the top, underground noise and glows red . A possible eruption would occur within months to years . The volcano is relatively calm , therefore recommended to monitor the volcano, educate and empower the authorities and local people, develop and practice emergency plans, evaluating and implementing mitigation measures and inform the authorities responsible for civil protection about volcanic activity , among other actions.
Yellow Alert . At this level , the volcano started an eruptive activity, which becomes permanent with small ash emission and lava flows . Besides the increased seismic activity and tremors are permanent and perceived by the population. The eventual eruption would occur within days to months. The public announcement of the emergency is recommended. It should review the equipment and relief materials , activate the emergency committees , conduct mock eruption and evacuation shelters and enable risk zoning , among other measures . This alert level means generally before a possible major eruption and may eventually lead to an evacuation.
Red Alert . The volcano has an important activity, which causes the formation of lahars , minor pyroclastic flows and pyroclastic fall of lava emission . This may reach the extreme case , corresponding to a major eruption , with pyroclastic flows , lahars bulky , total devastation in the volcanic area and eventual formation of a caldera. This major eruption happen in hours or days. For this maximum, the evacuation of risk areas is recommended and, if necessary, should reach the total evacuation of the volcanic area and further recommends a general alert around the volcano environment .