FIBER: MAYON VOLCANO: THE BEAUTY HAS FURY

Raffi Banzuela

A visit to the Bikol Region will be hardly complete without at least a glimpse at Mayon Volcano.

Mayon's conical symmetry makes here a very strong tourist attraction. A world wonder. Her fertile slopes and surrounding plains nurtured by abundant rainfall throughout the year makes the place where she is, a rich agricultural region.

But the beauty has savage tantrums!

She could be ugly and very destructive when restive as she is awesome during periods of repose.

Mayon Volcano is located in the province of Albay in the extreme southeastern part of Luzon. She is a strato-volcano.

Mayon is the most active in the Philippines. She has had a periodic eruption during the last three and a half centuries.

In fact, there had been periods in the recent past when Mayon erupted almost yearly. These eruptions have wrought untold destruction to lives and properties.

Typically, Mayon eruptions are "vulcanian," which means that these are explosive.

Records have it that since 1814 there have been some 50 distinct eruptions of Mayon. These eruptions and others to follow are better referred to as "eruptive states." When Mayon is in such mood, the same is not over within a single eruption but after a series of eruptions distributed generally over a month or two.

It appears in the records of the Commission on Volcanology (COMVOL), now the Philippine Institute of Volcanology and Seismology (PHIVOLCS), that the earliest eruption occured about 1616, but her first eruption to be described at length was that of July 20, 1776 which lasted six days.

1814

The most violent and destructive eruption known occurred on February 1, 1814. It was said to be preceded by local earthquakes the day before, continuing during the night and culminating in a violent upheaval at eight in the morning. During this eruption the areas surrounding the volcano were enveloped in thick ash showers while terrifying lightning discharges occurred within the dark eruption clouds. (I have a translation to Bikol of Fray Bernardino Melendreras' (1815-1867) ROMANSA BIKOL, an account of the 1814 eruption which has details not included in published reports.)

It is said that it left at least 1,200 dead (urban legend?) while severely damaging the town of Camalig and burying the burgeoning towns of Cagsawa and Budiao. Half of Albay District and Guinobatan were laid in ruins.

The great eruption of 1814 was then followed by a number of mild eruptions until JJune 1897 when another devastating activity occurred. Earthquakes, rumbling sounds, cfrater glow, and lava attended the activity. Incandescent rock materials were hurled as far as the Albay Gulf. Ashes fell within a radius of 80 kilometers, Hot blasts and rolling incandescent meterials killed some 300 people.

At the turn of the century, Mayon, after a relatively short slight eruption in March 1900, underwent a period of rest that lasted for 26 years.

Then in June 1928 she again erupted with fury. In 1938, ten years later, she was at it once more. There were minor explosions in August 1939, September 1941, 1943, January 1947, and April 1968.

She was restive again in April 1978 and September 1984. She surprised everyone with a rae "Nuees Ardentes" on February 2, 1993 killing 73 farmers in its wake. She was also active in 1999, 2000, and 2001.

Attendant dangers

From 1814 to 1993, eruptions occurred at an average of one every four years.

While eruptions themselves are never short of being spectacular, both visitor and native can never be free from the anxiety over the tragedy it will leave in its wake or even much later.

The Phivolcs cites at least six major attendant dangers during eruptions. These are: hot blasts, rolling incandescent materials, earthquakes, cold and/or hot mudflows/lahars, lava flows, and ash showers.

Hot blasts arise when pent-up gases are able to effect very rapid escape into the atmosphere. Blasts that are directed at low angles from the ground surface often do much damage and could cause a high toll in human lives. There have been reports of hot blasts originating not from the crater but from portions giving way to the advancing lava flow; these are local in nature and may not be very damaging.

During eruptions, incandescent fragments of varying sizes are hurled from the crater. While most of these materials settle down along the vicinity of the summit, still a considerable amount reaches the foot of the volcano by rolling, sliding, or somersaulting.

Very often, volcanic eruptions are preceded or accompanied by earthquakes. In fact, among all diagnostic criteria of an impending eruption, premonitory quakes are considered the most reliable. Opening of fissures, surging of magma, and subterranean explosions are heralded by them.

Among the strictly volcanic processes which widely distribute debris, both coarse and fine, are the volcanic mudflows or "lahars." Mudflows occur commonly in the vicinity of a volcano and help distribute and re-distribute the apron of volcanic ash deposited by various agencies around a cone after the materials have cooled and have become water-logged, perhaps due to torrential rains.

At various times, different sectors of Mayon have received mudflows. In fact, its broad gentle slopes are composed mainly of mudflows which carried down boulders of up to 1.5 meters in diameter, or even bigger, to great distances.

It is more likely that the high toll on human lives exacted in some violent eruptions of Mayon was not so much the result of hot blasts or to the fall of pyroclastic materials, but by large mudflows triggered either by the eruption or by heavy rains.

In the violent and destructive eruption of February 1, 1814, for example, field evidence strongly suggest that what overwhelmed and laid in ruins the towns of Cagsawa and Budiao was a huge mudflow or lahars.

Killer floods

There are on record at least two great disasters in the Mayon area not directly attributable to volcanic activity but to floods which caused volcanic materials to roll down to the plains and to the sea after the manner of mudflows, only with more mobility and with greater rapidity.

The first great disaster of this kind on record was in October 1776, when it was estimated that thousands of people perished and much property was destroyed.

About 100 years later, in November 1875, another flood caused heavy destruction and the number of victims was estimated at 1,500 saying nothing, of course, of the money value of the property damaged. There was one great flood on July 27, 1853 that damaged properties and crops in Ligao, Oas, and Polangui. Within the memory of the older residents of Albay was the flood of 1915.

While that 1915 flood resulted in no great loss of lives, it did damage to crops and covered the tracks of the Philippine National Railways, between Legazpi City and Sto. Domingo, with boulders of varying sizes, sand and gravel. The latest mudflow occurence was on June 30, 1981 which resulted in the death of 40 people. Estimated cost of damage to property was placed at millions of pesos. (This article does not include accounts about supertyphoon "Reming" (2006) which unleashed a very destructive mudflow.)

The extrusion of lava from the crater and from fissures opened at its slope have been two of the characteristics of most of Mayon's previous eruptions. In 1928, lava flowed towards Sto. Domingo but was able to reach only as far as the base of the volcano. In 1938, there were short flows in the direction of Sto. Domingo and Camalig. So was it with the 1947 eruption. Flows of the 1968 and 1978 eruptions were directed towards Camalig.,

Vulcanian eruptions, as Mayon eruptions commonly are, have "volcanic ash" as their chief product. Volcanic ash is, in the strict sense, fine materials, the size of sand grain and dust derived from new and old rock materials along the volcano's throat and crater. It is carried up by belches of volcanic gases during eruptions and then acted upon by prevailing winds. Thus the leeward portion of the volcano gets the shower of ash. Such showers could be highly destructive to vegetation and even to animal life, but the soil ultimately yielded by them is fertile.

And while Mayon remains to be a wonder to the visitor, Albayanos live with her in both anxiety and pride.

The 1999, 2000, 2001 eruptions

In June, July, and September 1999, Mayon went on a phreatic binge. On July 1, 1999 the rim of the volcano's caldera began to glow, sulfur dioxide output also increased. Those were precursors to a phreatic explosion on June 22, 1999. There were no earthquakes or lava flows reported. The eruption was sudden.

On July 6, 1999, national and provincial disaster management officials prepared to evacuate some 42,000 residents around Mayon as lava was noted to be moving within the magma chambers. It was on September 22, 1999 when Mayon threw up rocks and ashes six kilometers into the air for about four minutes. Burning rocks ignited bush fires in a gully on the volcano's eastern slopes. It was another phreatic explosion. Nevertheless, some 2,000 villagers fled from their residences.

Mayon was restive until March 2000. Its eruptive state was recorded starting January 5, 2000 when steam and ash plumes exploded six kilometers into the air. On February 15, 2000, villages within the six-kilometer radius from the volcano's crater were ordered evacuated. On February 22, 2000, the six-kilometer danger zone was declared a "no man's land."

On February 24, 2000, the volcano erupted and sent superheated ash into the air. The ash rained as far as fifteen kilometers away. Lava with temperatures that reached well above 1,000 degrees centigrade cascaded 3.5 kilometers down the volcano's slopes. There were loud rumbling sounds. Fourteen eruptions were recorded until later afternoon of this day, with the strongest sending ash darkening the horizon in some villages. The Air Transportation Office cancelled all airplane flights to and out of Legazpi City. Meanwhile, officials warned that a more violent explosion could occur at any time as the magma was still rising to the dome. The "big bang" came on February 28, 2000 with volcanic eruption levels successively raised from 4 to 5. Boulders as large as cars were being shot half a kilometer up into the sky. Some 50,000 people were brought to emergency shelters. On March 1, the volcano continued to hurl rock as big as houses and cars. The number of evacuees ballooned to 83,000. The entire province went powerless as high voltage lines of the National Power Corporation's sub-stations in Ligao City and Guinobatan were short-circuited by ash falls.

Statistics from the Provincial Disaster Management Office (PDMO) had it that the 2000 eruptions destroyed 6,789.02 hectares of rice land worth about P159M; 2,690 hectares planted to corn worth P42M; 808.39 hectares planted to vegetables worth P59M; 22,732.79 hectares of coconut land worth P19.5M. With the damages to bananas, root crops, fruit trees, and papaya, the total agricultural land damaged was 33,441.63 hectares with an estimated value of P283,834,011.22.

Mayon Volcano again erupted on June 24, 2001 at 12:15 p.m. hurling superheated, chocolate-colored ash columns that blossomed into cauliflower-shaped clouds some five kilometers high darkening the skies and showering ash on surrounding villages. The Phivolcs immediately raised the eruption alert status to 5 which meant that a hazardous eruption was in progress. The previously delineated seven-kilometer danger zone was extended to eight kilometers which must be "vacated due to possible occurrence of pyroclastic flows and associated explosions. Some 11,156 persons from five barangays in Legazpi City were immediately evacuated.

Ash and sand showered the towns of Camalig, Guinobatan, and Ligao City. Half an inch of ash fall covered parts of Camalig and the poblacion of Guinobatan. Motorists have to switch on headlights to see the road. That, on a usually bright early afternoon.

The Phivolcs described the June 24, 2001 eruption as "vulcanian" in character. The next day saw the number of evacuees grow to 28,439 distributed in 16 evacuation centers. The provincial government declared a state of calamity in albay excepting the towns of Rapu-rapu, Manito, and Pio Duran.

On July 27, 2001, after a month of relative clam, Mayon erupted again at 7:56 a.m., this time with much violence that seemed to turn the day into night. Residents wee scared. Huge volumes of lava, car-size rocks and pyroclastic debris formed a cauliflower-shaped column that leapt up to ten kilometers into the air. The ash mixed with rain, blackening the morning sky.

Residents observed that this eruption was the strongest and more frightening yet compared with those within the last three years. The thunderclaps, the rumbling sounds, the tremors were louder, more sustained and stronger.

Mayon is at repose again. The residents at her base have gone back to their homes. Life is back to "normal." There are no hard stares at the mountain now. Only furtive glances not so much at the mountain's crater but perhaps to the direction of a "Sagoksok" gadding about the under brush in search of a worm for an late afternoon feed.