1 College of Public Administration, University of the Philippines, Diliman, Quezon City, Philippines.
Barangays Parulog and San Antonio, Bacolor, were hit by lahars in 1991 and by flooding in 1992. One hundred nineteen of 143 respondent families received lahar warnings, and, of those, all but 8 evacuated at least temporarily, at least once. However, false alarms and sometimes inadequate evacuation facilities raised skepticism in 1991, and a generally improving outlook in 1992 brought many evacuated families back to their homes.
Warnings could be improved by the addition of village-level, house-by-house hazard maps, vesting of sole warning responsibility in Barangay Disaster Brigades, identification and use of proven warning strategies, and recognition that warnings will only be heeded if adequate transportation, shelter, and livelihood can be provided to those who evacuate.
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Preparations made by households for the eventuality of a natural hazard are based on their knowledge of that hazard. Such knowledge is normally acquired from repeated encounters with a hazard, from which its observable precursors are identified, its recurrence frequency ("repeat time") is approximated, and practical steps toward its mitigation are learned. For example, people living at the foot of Mayon Volcano use folk precursors and a supposed 10-year repeat time to anticipate eruptions (Zarco, 1985), and people that live in typhoon-prone areas now build their houses to withstand wind (Cola, 1993).
However, households in central Luzon did not have such knowledge about lahars. No oral tradition survived from the previous eruptions and lahars of Pinatubo, and, initially, the populace could only respond in a haphazard and frantic manner. Subsequent warnings about the nature and occurrence of lahars have saved lives, but, even now, some weaknesses remain in the lahar warning process.
Lahar warnings are issued for two timescales at Pinatubo: long range and short range (Janda and others, this volume). Long-range warnings consist of hazard maps, briefings, brochures, booklets, flyers, posters and leaflets, prepared and given (hopefully) long before actual lahars. The hazard maps indicate the degree of hazard to which each area is exposed. Some of these materials outline precautionary actions that can be taken to reduce one's risk.
In contrast, short-range warnings are issued minutes to days before the onslaught of lahars. Warnings are based on meteorological forecasts, realtime rainfall data, and instrumental and visual observations of lahars at forward (upslope) observation points. Short-term warnings are announced over the radio, through local authorities, or, in symbolic form, through the sound of gunshots and the pealing of church bells. They may also be attached to typhoon warnings. Three levels of short-range lahar warnings are issued at Pinatubo: level 1 (rainfall on Mount Pinatubo and vicinity), level 2 (rain has occurred for 30 min at critical intensities), and level 3 (lahars have been observed) (Philippine Institute of Volcanology and Seismology, 1993).
Long-range warning materials are issued mainly by the Philippine Institute of Volcanology and Seismology (PHIVOLCS), but the National Mapping and Resource Information Authority (NAMRIA), Bureau of Soils and Water Management (BSWM), and the National Economic and Development Authority (NEDA) have also produced materials. Short-range warnings are issued by the Office of Civil Defense (OCD), through local (regional, provincial, municipal, and barangay) disaster coordinating councils. Lahar watchpoints that are supervised by the OCD also directly disseminate warnings to those at risk.
The primary data used in the study were gathered by students through interviews of household and key informants and by onsite observation (table 1). The survey covered 143 households in Barangays Parulog and San Antonio, Bacolor, both of which are immediately east of the Pasig-Potrero River, and both of which were hit by lahars in 1991 and floods in 1992 (fig. 1).
Figure 1. Location of barangays San Antonio and Parulog, Bacolor.
Table 1. Questions asked of household heads, Parulog and San Antonio, Bacolor, and tubulated answers.
[Questions were asked in Tagalog]
According to the 1990 census, Parulog had a total of 321 households before the eruption of Mount Pinatubo, and San Antonio had 887 households (National Statistics Office, 1990). One hundred forty-three households (about one of every six) were asked about their receipt of and response to warnings about lahars. Any adult was allowed to serve as a respondent, but most of those who responded were either the father or the mother in a family. Interviews were in October and November 1992 in the affected barangays and in evacuation camps.
Seven key informants were also interviewed: two who never moved out; two who moved out and later returned; one who moved out and has not returned; and two who were familiar with the warning system in the site and willing to discuss it. Three of these key informants were recommended to the author as being articulate and knowledgeable on the topic; the others were interviewed because they were available during the author's field work and willing to tell their stories. Interviews with key informants were unstructured and aimed to draw out the experiences of the informants.
Although the questionnaire did not distinguish between lahars of 1991 and floods of 1992, a subsequent visit by the author to these barangays ascertained that responses referred to lahars and lahar warnings of 1991. The questionnaire did not distinguish between long-range and short-range warnings, either. Most respondents spoke of immediate, short-range warnings, though a few referred to warnings received weeks and months before lahars hit their barangays.
Eighty-three percent of the households heard warnings of lahars before their barangays were hit. Long-range warnings that their barangays were at high risk had been issued as much as 3 months before lahars came, but only eight households reported receiving such warnings. Instead, most received warning within the week of the lahars. Apparently, long-range warnings lacked dissemination and (or) attention-getting impact. One reason might be that the basis for long-range warnings is not readily observable, except by relatively mobile or media-exposed persons. This was suggested by the warning path to a professional in Barangay Parulog:
The first time I learned that we are in a very risky area was from a poster in the DSWD [Department of Social Welfare and Development] office in San Fernando, Pampanga, 3 months before the lahar came. But I thought that the lahar would not come, contrary to what the poster said. I later read about it in a newspaper. I wanted to move out from the barangay but I have my family, house, and land here. So I stayed.
The greater effectiveness of short-range warnings results from immediacy of the event and the manner in which the warnings are conveyed. Local officials themselves announced the short-range warnings. Forty-five households heard short-range warnings from barangay officials, while 22 additional households were warned by municipal officials. Twenty-three households received the warning from policemen and military personnel, and 20 households got the message from the parish priest of San Antonio, who rang the church bell as a warning. Others received warnings from television, radio, and other barangay members. Although a few were not reached by any warning, many received warning from two or three sources. The manner in which the warning was made in San Antonio is described by one resident:
The municipal government has a lahar monitoring team. The mayor has stationed persons along the river channel to observe if lahar is coming. These persons are equipped with hand-held radio and they call our parish priest and local officials [who were also provided with radios] when they spot the coming of lahar. The Barangay Council sounded the siren while the parish priest tolled the bell. My family moved out from the barangay. We brought some items for our immediate needs but not everything because sometimes we do not believe warnings.
The last-mentioned skepticism arose because a number of warnings had been issued before lahars actually reached their barangays. Thus, long-range warnings had limited coverage and impact, and short-range warnings had better coverage, but their effectiveness was partly compromised by prior false alarms.
Among the households that heard a warning, 93 percent responded to it. The response depended on which warning they took seriously. Many of those who ignored previous warnings and responded only to the one issued shortly before the lahar came immediately ran to higher places bringing nothing with them. About 50 households responded in this manner. Among those who took heed of earlier warnings, 33 households managed to pack some of their things before moving out. Part of the preparation made by 12 families was to transfer their household items to the elevated portion of the house. Three families took their children to a relatively safe place. Two families reinforced their houses to withstand the force of lahars.
Whether a family heeded the warning depended on a number of factors. These include the degree to which the family's sources of livelihood are tied to its home and nearby farmland, their home's perceived vulnerability to lahars, the ease with which the family could move from the risk area, and the comfort available in a prospective shelter. Two different responses are illustrative. According to the head of one family in San Antonio that decided not to move out in spite of the warning,
The warning was too short. My family could not move out because the road to the highway was clogged with vehicles. Everybody tried to get out from the barangay. Besides, we have a number of goats and ducks that we could not bring with us. The evacuation site is too crowded. I was confident that, if the worst situation occurred, I could bring my family to my roof, which is made of galvanized iron. The lahar came about 7:15 in the evening, while we were watching a Filipino action movie on the television. We heard a rumbling sound and we all ran to the roof as the lights went out. But my neighbors also climbed onto my roof because it was higher than theirs. I estimated the lahar must have been about 15 feet high. There were about 50 of us on my roof. We stayed there until 11:00 in the evening because we waited for the rain to stop and the lahar to subside.
The decision to move as warned was swifter if a family felt vulnerable to the hazard, if the prospective shelter was comfortable, or if the family's livelihood would be unaffected by the transfer. These factors were apparent in the account of one family in Parulog:
We received the warning from the mayor. We used to plant vegetables here but we decided to move out early from the barangay because my mother is paralyzed. It would be very difficult for us to run from the lahars with her condition. Nor do we have a private vehicle to take us out at any time. We took public transport to Mexico, Pampanga, where my aunt has a house. My husband works in San Fernando, Pampanga, and he also urged us to move out. He knew that lahar would definitely come because he works with the Department of Public Works and Highways. We stayed with my aunt for 3 months and did not experience what our neighbors went through.
Households that moved earlier were able to bring along more than just their clothes. Twenty-four households brought with them their kitchen utensils, and 29 carried appliances to their temporary refuge. Some 43 households reported being helped by their relatives when they moved out. Some were able to take buses sent over by the mayor. Half of the families that moved out stayed temporarily with their relatives in other parts of central Luzon and in Metro Manila. A few opted to rent living quarters in San Fernando, Pampanga, or in Metro Manila.
Households that were without relatives willing to take them in or that lacked the means to rent living quarters moved to government- and NGO (nongovernmental organization)-run evacuation centers. Eleven respondents said the living quarters were too hot during days and too cold at night. Nine respondents were concerned about the lack of toilet facilities and eight found the evacuation centers too congested.
More than 60 percent of the residents of Parulog and San Antonio were born and had lived in those barangays until lahars came. Those who evacuated longed for the community that had nurtured them and had provided them with the sense of security produced by generations of patterned interactions. Leaving their community entailed changing one's economic base and also leaving a social world in which they were adept and comfortable. Lahars brought both physical displacement and social upheaval.
At the time of our interviews, Parulog and San Antonio were still partially depopulated. In Parulog, only 50 households remained out of the original 321, while in San Antonio, 528 of 887 remained. But some who moved out are trickling back to their homes. Those who remained are gradually rehabilitating their farmland and adapting to the physical reality of annual lahars and floods. Short-term crops such as peanuts and tomatoes are planted instead of annual crops so that these can be harvested before the annual onset of lahars. Thin lahar deposits at some distance away from the main channel are slowly being removed or mixed with underlying soil, and crops are planted and harvested during the dry season. Long-term investments like livestock and poultry raising are still being avoided.
The ability of those households to adapt to a new condition in the face of lahar threat is illustrated by one key informant's family that was living in a house half buried by lahar deposits. The condition, in 1992, was described by the housewife as follows:
The barangay captain urged us to move out, but we insisted on staying. The heat in the evacuation center is unbearable, and there is not enough space for my six children. Besides, we feel secure [mapalagay ang loob] in this village because everyone knows how to deal with us and we know how to deal with them. My children can play outside our yard, and my neighbors can keep an eye on them. The house can be left open when we are away and nothing is lost, because my neighbors can recognize any stranger who might come in. Most of our neighbors are related to us by blood or by affinity. We all grew up here, as did my parents and my neighbor's parents and grandparents.
My family put the sandbags around the house to minimize deposition. The jutebags were given to us by the municipal government. Floods last only for 20-30 minutes and we just stay on the roof when they occur. When the lahars are intense, we move to a safer area nearby. There is always a safe area because, unlike water, lahars have a new channel every time they flow down. After the lahars, we remove the water that seeped into the house. Our appliances are secured in the upper story which we constructed recently. When lahars cease, we resume our normal activities. Now I am growing sweet potato and cassava in the lahar deposits around the house. We can start to harvest these in 2 to 3 months.
The longing of other, former residents to return to the village is dramatized by a family that is now living in San Fernando, Pampanga. The mother provided this account:
On Sundays we still return to the village to hear Mass. I get to meet my old friends and neighbors on this occasion. I used to have a poultry farm in the village, but it was swept away by lahar flow. We now have a house in San Fernando, and my children are going to school there. But I still plan to go back to the village where I grew up. When I work there, I feel I am serving my own people.
The present warning system against lahars works, but it could be improved. First, village-level hazard maps should indicate those houses at greater and lesser risk so that families can make commensurate preparations. Such preparations can include arranging with relatives for temporary shelter, moving heavy and expensive items before lahars actually occur, formulating escape strategies with household members, and reinforcing houses against deposition and flooding.
Village-level hazard maps can also serve as a basis for a community evacuation plan. It can pinpoint households that need priority for evacuation, suggest the most practical escape routes, and identify relatively safe spots that can serve as pick-up points or temporary refuge for evacuees. Such maps would also show which households need to receive short-term warnings first. At the same time, village-level maps would identify any less-vulnerable households that no longer need to be evacuated. In this way, such households would not be inconvenienced, and the credibility of the warning system would be improved.
Another potential improvement would be to place the sole responsibility for warnings with the Barangay Disaster Brigade. Having one source of warning would prevent the spread of varying interpretations of the lahar situation, establish accountability for warnings, and facilitate audits to ensure that every concerned household receives warnings. The Barangay Disaster Brigade is best positioned to issue warnings because it has well-understood legitimacy and a major stake in the well-being of the village. Because its members are villagers themselves, the Barangay Disaster Brigade can readily assist households who evacuate, assign roving teams to safeguard deserted houses from looting, and eliminate unnecessary filters (government offices and mass media) that often cause miscommunications.
Third, continuous assessment of the lessons from each warning and response would help concerned agencies to sort out workable from nonworkable strategies. The assessment would be done by end users of the warnings, government personnel who manage the warning system, and scientists who provide the initial warnings.
Fourth, it is clear from the respondents of this study that the warning system does not work in isolation but as part of a continuum of measures intended to reduce destruction. A warning system cannot be effective if households are physically unable to move, if evacuation camps are unattractive alternatives to staying at home, if there are no alternate sources of livelihood, or if people do not feel that they are threatened. The warning system must be complemented by a well-conceived and well-implemented set of preparedness, rescue, and relief services.
Postscript: On the night of September 22-23, 1994, breakout of a lahar-impounded lake on the slopes of Mount Pinatubo generated a major lahar that once again buried San Antonio and Parulog. Many houses that had been only slightly buried in 1991-92 were buried up to the eaves of their roofs. Ample long-range warnings had been given; few or no immediate warnings were issued, and many residents were forced to take refuge on their rooftops.
Cola, R.M., 1993, Disaster warning in Metropolitan Manila: Content, communication, and consequence, in Disaster prevention and mitigation in the Manila Metropolitan area: Quezon City, PHIVOLCS Press, p. 134-153.
Janda, R.J., Daag, A.S., Delos Reyes, P.J., Newhall, C.G., Pierson, T.C., Punongbayan, R.S., Rodolfo, K.S., Solidum, R.U., and Umbal, J.V., this volume, Assessment and response to lahar hazard around Mount Pinatubo, 1991-93.
National Statistics Office, 1990, 1990 Census of population and housing: Population by city, municipality, and barangay (Pampanga): Manila, National Statistics Office, Report no.2-74C, December 1990.
Philippine Institute of Volcanology and Seismology (PHIVOLCS), 1993, Pinatubo Volcano lahars: Quezon City, PHIVOLCS Press, 31 p.
Zarco, R., 1985, Anticipation, reaction, and consequences: A case study of the 1984 Mayon Volcano eruption: Quezon City, Philippine Institute of Volcanology and Seismology, 21 p.
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Contact: Chris Newhall
Last updated 06.10.99