Ojo que para determinar la influencia de un erupción en el clima no solo juega la altura de la columna eruptiva también la composición de la misma que como regla y a los efectos climaticos se refiere emiten So2 y Co2 , pero hay veces que por el tipo de volcan este emite en relación más cantidad de otros compuestos como el Co2 y muy poco So2 que es el que enfría al llegar a la troposfera. Un ejemplo de esto es la erupción del chaitén , la columna llego a los 30km de altura de sobra para llegar a la troposfera, pero tuvo poco efecto en el clima ya que emitio poca cantidad de So2
Sin embargo, Stern indicó que son escasas las posibilidades de que el cono de cenizas pueda influir en el clima de la Tierra, como ocurrió con las erupciones del volcán Monte Pinatubo, en Filipinas (1991) y con el Tambora, en Indonesia (1815).
"Para influir de manera significativa en el clima, un volcán tiene que propagar mucho dióxido sulfúrico en la estratosfera durante un periodo prolongado. Nuestros datos muestran que en la última erupción del Chaitén ésta ha tenido un alto contenido de óxido silíceo y ha sido baja en azufre", indicó.
Por el contrario, la del Pinatubo, que enfrío el clima mundial durante alrededor de un año, tuvo grandes emisiones de dióxido sulfúrico.http://www.terra.cl/actualidad/index.cfm?id_cat=302&id_reg=967080El pinatubo si llego a liberar gran cantidad de So2 y la columna eruptiva llego a los 34km de altura
1991 eruption
On 16th July 1990 a magnitude 7.8 earthquake hit 100 km northeast of Mt Pinatubo.
3rd August 1990
Loud rumbling heard, a landslide near the summit, and steaming ground. First volcanic activity in 400 years.
August 1990
Five earthquakes near Pinatubo.
15th March 1991
Rumbling and earth tremors.
2nd April 1991
Steam and ash exploded from a 1.5 km long fissure high on the northern slopes of Pinatubo. Smell of sulphur and ash fell 10 km away.
3rd April 1991
200 small earthquakes registered at the volcano.
23rd April 1991
US Geological Survey arrived with monitoring equipment.
26th April 1991
Monitoring station set up at Clark Air Base 25 km to the east of the volcano.
13th May 1991
30-180 earthquakes per day were being recorded. Volcano releasing sulphur dioxide indicating molten magma was rising beneath the volcano. Alert level 2 issued.
23rd May 1991
First hazard map completed.
28th May 1991
A tenfold increase in sulphur dioxide emissions in previous 2 weeks.
1st June 1991
Earthquakes became centered 5 km below the volcano.
5th June 1991
Sulphur dioxide emissions almost stopped as the vents became blocked. Earthquakes continued and the mountain started to bulge as magma moved towards the surface.
7th June 1991
1500 earthquakes under Pinatubo. An ash eruption sent a cloud to 8 km high. Alert level 4 issued stating an eruption could happen within 24 hours. Danger zone extended to a 20 km radius.
Lava reached the surface and formed a small dome 1 km northwest of the main crater.
9th June 1991
Sulphur dioxide began escaping again from the volcano. The first nuee ardentes rolled down the volcano. A large eruption of ash. People evacuated from a 20 km radius.
10th June 1991
Evacuations begun at Clark Air Base. (14,400 people)
12th June 1991
Ash eruptions to 20 km above the volcano on Philippine Independence Day.
13th June 1991
Ash eruption to 25 km high followed by 28 hours without an explosion. Earthquakes continued.
14th June 1991
Violent explosion at 1:09 pm. Eruption column to 21 km in 15 minutes. Nuee ardentes devastated the main valleys radiating from Mt Pinatubo.
15th June 1991. The Main Eruption
Typhoon Yunya passes 100 km northeast of Pinatubo. Mudflows raged down the mountain at 30 km/hr. At 3:39 pm the main eruption began. In 9 hours 90 percent of the total material for the eruption was expelled from the volcano. Cauliflower columns of ash, gas and steam rose 34 km high and traveled 400 km. At 4:30 pm the summit of Pinatubo began to sink. The evacuation area was increased to 40 km radius. The eruption stopped at 10:340 pm.Effects of the Eruption
740 people killed.
A huge caldera was formed 2.5 km across.
260 m was lost off the summit of the volcano.
The ash entered the stratosphere and covered the whole earth within 12 months.
Global temperatures were reduced by 0.5 degree C the year after the eruption.
Forests buried under 50-200 m deep ash and pumice.
During the last five months of 1991 200 mudflows raced down the valleys of Pinatubo.
Damage amounted to $450 million dollars.
8,000 houses were destroyed and 75,000 houses damaged.
2 million people were affected by the eruption.
The biggest volcanic disaster of the 20th century was avoided due to good planning and monitoring.
http://www.volcanolive.com/pinatubo.htmlSaludos..
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