IMPACTS OF VOLCANOES ON CLIMATE

• EXPLANATION
  • THE FALL OF TEMPERATURE
  • DECREASE OF THE STRATOSPHERIC OZONE LAYER
    
    
• MEASURES OF THE VOLCANIC ERUPTIONS
  
  
• TYPES OF ERUPTIONS

HISTORICAL ERUPTIONS THAT HAVE THE MOST INFLUENCE ON THE CLIMATE

THE MAYON :
On 04/10/1992 and 02/24/2000 ) in the eastern Philippines the Mayon has emitted a column of smoke and ash that reached 13 km altitude. This volcano is among the most dangerous and active on Earth. In 2000 volcanic ash rains plunged the villages into darkness at the foot of the Philippine volcano Mayon up to 12 km from the crater.

These last 400 years it has been 49 times in eruption, the most important was in 1814 when the summit of Mayon exploded. The following year, in Indonesia, the Tambora erupted. These volcanoes, particularly the Tambora had a significant effect on climate.

Click here for the eruption of Mayon in 2000.

THE HUDSON :
From 15 to 21/08/1991 the Hudson volcano in Chile exploded. A cloud of dust amounted up to 18 km in height and it steered for south from the southern end of America by surrounding the Antarctic continent. The cloud had 250,000 tons of sulfur dioxide, dispersed in an area of 270.000 km². From the ashes of this volcano was found in Antarctica.

THE PINATUBO :
On 11/07/1991 in Philippines, the Pinatubo erupted while it was dormant for over six centuries. A total of 20 million tons of sulfur dioxide were released into the atmosphere at a height of 20 km. All this gas caused the reduction of 1 to 5% of solar radiation received on the earth, or -3,50 W/m², resulting in a drop in temperature of 0,10 to 0,50°C and 1,50°C at high latitudes for about 3 years. In the stratosphere, the presence of a cloud composed of volcanic fine particles accentuated the red tones of the sky at night which gave a real blaze of heaven. Researchers assume that the hurricanes Andrew and Iniki in fall 1992, as well as heavy rainfall in the US Midwest in the summer of 1993 could be the consequences of the atmospheric effect of this eruption.

THE NEVADO DEL RUIZ :
On 11/03/1985 in Colombia the Nevado del Ruiz, which rises to 5390 m altitude has ejected 0,56.km³ stratospheric aerosols. From the 11/13/1985 the ashes have covered the area by more than 15 km radius.

It was the deadliest eruption with 24,000 deaths.

Its latter most important eruptions were in 1985 (VEI 3), 1845 (VEI 3), 1595 (VEI 4), 1350 ?(VEI 4)...

EL CHICHON :
On 03/29/1982 in Mexico, El Chichon has ejected into the atmosphere up to 20 million tons of sulfur which is mounted at 35 km. This cloud has moved both east and west under the influence of winds blowing in different directions depending on their altitude. The volcanic cloud has triggered a series of optical effects. In Arizona, abnormally long and brilliant sunsets occurred. This volcano sent so much ashes in the atmosphere than the sky was darkened for 2 days. After the eruption of Chichon, the temperature of the Earth has decreased by about 0,30°C !

According to some experts this eruption may have had other effects on Earth's climate. It might cause a sudden change in atmospheric and oceanic circulation in the equatorial regions of the Pacific Ocean, which would have had an effect on El Niño. The consequences were abnormal weather on the South American continent.

THE MOUNT ST-HELENS :
After more than a century of rest, the 05/18/1980 in United States the Mount St-Helens volcano woke up and it exploded with an energy equivalent to 500 times that of the Hiroshima bomb after the soil had risen by 1.50 meters every day. The ashes and volcanic dust amounted to 20 km in the stratosphere and circled the Earth in 15 days. These 540 000 tonnes of stratospheric aerosols have reduced the temperature of the northern hemisphere of 0,10°C. During the eruption in a town about 430 km from the volcano almost a centimeter ash fell. The breath of the eruption approaching the speed of sound, destroyed everything within a radius of 27 km. After the eruption the volcano lost 400 meters of altitude.

According vulcanologist studies from 10.000 years the Mount St. Helens experienced a major eruption by century. He had an activity in 1800, 1813, 1831, 1836 and sporadically between 1842 and 1857. Its last eruptions were in 1957, 1980, 1986, 1991.

Click here to see a video of the eruption of Mount Saint Helens

AUGUSTINE :
On 01/22/1976 the Augustine volcano in Alaska in the US awoke. A column of ash that rose during the eruption disrupted air traffic and ash fell in Anchorage. The 0.60 km³ d'aérosols qui c'est élevées dans la stratosphère ce qui a perturbé le climat de la Terre.

THE SOUFRIERE :
This volcano in the southern part of the island of Guadeloupe, of an altitude of 1467 m, is a stratovolcano whose summit is a dome.

10 eruptions of explosive type occurred since the sixteenth century whose two most intense phreatic eruptions occurred in 1797/1798 and in 1976/1977 with 26 major explosions in the ultimate of the last major explosive eruptions.

The last major eruptions were those of 1902, 1913, 1914, 1917, 1976/1977. This one of 1812 had much effect on the climate all the more than the same there was the eruption of Awu Indonesia followed by the eruption of Vesuvius in 1813, the Mayon the following year and the Tambora in 1815.

THE KATMAI :
On 06.06.1912, the highest volcano at 2 450.m altitude, located in Alaska, erupted after a very long and very violent seismic crisis. It ejected 12 Km³ of magma on Earth and sent 20 million tons of sulfur into the atmosphere or 35 km³. This has reduced the temperature of 0,20°C. The days that followed the eruption it was night.

The explosion of Katmai was one of the strongest happened in history of Alaska. It was heard to 1600 kilometers around. Then the ash fall has been so significant that at 160 km from the volcano the roofs of houses collapsed. This was the 4th largest eruption of these 100,000 years after the Toba, Tambora and Taupo.

The eruption made it loose 400 m and its summit is being cut by a caldera of 4 km in diameter and 600 m deep. A dome (the Novarupta) of 250 m in diameter and 60 m height was formed at the end of the eruption.

THE MONT TARAWERA :
The night of 06/09/1886 in New Zealand a violent eruption broke out northeast of the island. This began with the summit of Mount Wahanga which was literally blown forming a thick black cloud that created a storm. Then still in the night the Mount Tarawera and Ruawahia entered in eruption.

During the eruption a volume of 0,30 Km³ dof ash is estimated to have been ejected over more than 16.000 Km². The eruptive cloud would have reached a height of 10 km altitude. Only 2.Km³ lava were ejected. Three Maori villages were buried. A long crack of 17.km has been created during the eruption. (see cons).

The largest eruptions of the volcano took place in : 1886 (VEI 5), 2880±20 BC (VEI 6), 5330±20 BC (VEI 5), 6580±20 BC (VEI 6).