It is not true that Taal is a small volcano. It is a volcano within a volcano. The entire 234 sq. km. lake is the caldera of a huge ancient volcano that blew its top in prehistory.
Therefore, it is also not true that Taal’s most violent explosion happened in 1754. The most violent eruption created that stunningly beautiful lake that hosts Volcano Island.
Before the 1754 eruption, a channel wide and deep enough to allow galleons to pass through connected the lake to Balayan Bay. This eruption, which went on for seven months, closed the channel. Where the channel was, Lemery now sits.
It is understandable that the land covering what was once a large channel is unstable. That explains all the fissures that appeared over the past few days.
It may be hard to imagine this: those sitting on Tagaytay Ridge enjoying the majestic views are actually sitting on the edge of the ancient caldera. They are not close to a hyperactive volcano. They are on the volcano.
On Volcano Island, there are 47 craters and fours maars (vents created by steam explosions when lake water came into contact with magma). We do not know how many craters and maars there are beneath the surface of the lake.
This is the reason why Taal is described as a “complex” volcano. Being a volcano within a volcano, we really have no idea of dynamic systems deep in the bowels of the mountain. Because this was once a large volcano, it could be drawing magma from many chambers very deep beneath the surface.
In a word: it could produce an extremely destructive volcanic event affecting one of the most crowded areas of the country. It could be a calamitous event that will make 1754 look minor. But that is too terrifying a thought. Science does not enable us to go on with this line of thinking without straying into speculation.
Because of Taal’s characteristics, a small volcano sitting on the remains of a much larger one, the danger zone is really much wider than what has been officially declared. Phivolcs is correct in not causing undue alarm by speculating on the worst possibilities.
We would rather think of this looming danger in the proportions of the last eruption that happened in 1977. That was a small, eminently manageable volcanic event. In a matter of days, we cleaned up the ash and went on with our lives.
This eruption appears to be different, however. The hundreds of quakes attributable to volcanic activity suggest that.
Phivolcs is maintaining Alert Level 4, warning that a potentially hazardous is imminent. The agency’s scientists have been looking after this volcano, often as a temperamental pet and sometimes as a lifelong vocation. They know that something different is happening this time.
‘Imminent’ is a rather flexible term. An eruption could happen in hours, or days, or weeks or even years.
We tend to be impatient with calamities that unfold. We somehow want them to follow our own life cycles, conform to our deadlines.
But our notion of time is different from geological time. Volcanoes may look the same. But each is unique. Each behaves according to the specific set of conditions governing their activity.
Popocatepetl, about as close to Mexico City as Taal is to Manila, began erupting in 1995. It is still erupting. No one knows when it will stop.
In the case of Taal, Phivolcs raised Alert Level 1 early in 2017. Nothing happened for months, save for some barely detectable rumblings deep in the mountain’s bosom.
It is not true what one congressman claims that the authorities did not warn us about Taal. We have been told for years that something was bound to happen with this volcano. But geological time is different from human time.
Last Sunday, alert levels were raised in quick succession as the volcano suddenly spewed ash. By Monday morning, some magma was expelled. Then the mountain appeared to relax.
It is not time to be complacent, however. Our scientists are saying that it is possible the worst is yet to come. This is why alert levels are kept at their highest.
Bless our scientists. They keep our politicians and their near-term impulses at bay.
The coming period will be a great test of patience for many of us. The people collected into evacuation shelters will be agitating to return to their homes as soon as the dust cloud clears. They will have to be restrained from doing so.
Food supplies will be a problem as evacuation of tens of thousands stretch out indefinitely. Civil society networks need to be mobilized to sustain a cadre of donors and an army of volunteers to keep the support going if we have to wait weeks and even months for the climactic eruption to happen.
Some of the areas already hit by the ash cloud or could be damaged further by a strong eruption will probably need to be abandoned. The communities will need to be resettled and new livelihood found for the victims.
Children suffer the most during calamities. Some way needs to be found to sustain the education of young evacuees if this situation goes on for a longer term.
A party-list representative demanded that government do something about the fish in the lake threatened with extinction. That should be low on the list of priorities. Worry about the people first.
Eventually we might need to reconfigure human settlement policies around this perilous lake. This is not the last eruption we will have to deal with.
Credit belongs to : www.philstar.com