prognosticate when a volcano will erupt is a complex and somewhat Sisyphean task . When a team of volcanologists think that they ’ve pass with flying colors just how to tell when an eruption will occur , a separate volcanic consequence or an unexpected blast show them that there ’s still a lot to learn .
late studies all seem to have one thing in mutual , though : Immediately before an eruption is due to take home , there issome sorting of activityat the vent or just beneath the surface , whether that be asudden uptickin gaseous emissions , terra firma deformation , smaller ruptures at the airfoil , or – most significantly of all – seismal activeness .
Writing in the journalEarth and Planetary Science Letters , a team of geophysicist have amount to a rather striking conclusion : In some cases , there is dead no activity prior to a volcanic eruption , somewhat in the same way that there is no bodily function straightaway preceding a major temblor along a fault occupation .
Telica Volcano , the caseful study for this special piece of enquiry . Riderfoot / Shutterstock
“ It is the proverbial calm before the violent storm , ” leash source Diana Roman , a volcanologist at the Carnegie Institution for Science , said in astatement .
The team focalise their effort onTelica Volcanoin Nicaragua , a tall , dangerous stratovolcano in the same category as Mount St. Helens . They began monitor this little ardent flock in 2009 , and by 2011 , they had a net of equipment analyzing every possible strong-arm characteristic of the volcano within a 4 - kilometer ( 2.5 - mile ) r .
Generally , when a vent is about to erupt , volcanologists look for several monition sign that broadly speaking employ to many form of volcano – particularly the explosive character . If the reason swell up , it designate that the magma informant in good order beneath the surface is fill up and increasing pressure on the border stone . If an increase in gas – like sulphur dioxide , carbon copy dioxide or water vapor – are notice at the vent , then magma is likely to be right below it , decompress as it ascends .
sure seismic waving approach pattern indicate that magma is mechanically forcing its way through the shallow rock’n’roll . This could either mean that a shallow magma chamber is meet up , or that this magma sleeping accommodation is unleashing its molten contents up through a conduit to the open . In most cases , one of these three type of activity introduce an eruption .
However , it appears that Telica was break the rules , at least from 2009 to 2013 . During this clock time , around 50 discrete volatile events occurred , and unusually , 35 of these were preceded with full point of no seismic activity lasting at least 30 bit . Only two of the 50 hap with prior seismic activity , with the remainder happening after a five - second - long interval of inactiveness .
In addition , the squad found that the long the period of inactivity , the more energy that the volcano later on released in an explosion . In fact , the largest detonation required a silent build - up of 619 minutes ( 10.3 hours ) , liken to relatively small-scale ones that occurred after just six minutes . They surmise that the oven broil flatulency try on to drive its way up to the control surface is sometimes blocked , and the longer it consume for this stop to be actuate , the more pressure accumulates .
The magma informant at Telica must be extremely explosive rich to produce so many petrol - drive explosions . toangsorry / Shutterstock
It must be stress that although Telica provided some splendid high - resolve datum , it is just one illustration , and one that likely only applies to throttle - rich ( “ fickle - rich ” ) seed of magma . Many volcano erupt in many different style , and it is true that many do show increase seismal activeness prior to any explosive periods .
Nevertheless , it ’s an intriguing discipline , and in the notoriously slick business of prognosticate eruptions , every small bit helps .
