Today marks the 10th anniversary of the July 16, 1990 earthquake, which shook up several parts of Luzon, including Manila, and left over 400 people dead in Baguio. Most of the fatalities were buried in the rubble that used to be the Hyatt Terraces Hotel and the Hotel Nevada. Since then, officials and residents have been alert for signs of any impending temblor. Yet at the same time, they seem to be ignoring the existence of other disasters waiting to happen here.

As in Payatas, haphazard urban planning, lax rules and the sheer lack of political will here in Baguio have combined with the ever increasing migration of poor people from other areas to ensure that hazardous sites host thousands of residents.. Such a situation guarantees that should any disaster strike, there would be a high casualty count.

Baguio is certainly not alone. Other places in the country have a similarly high potential for disaster. But the fact that 14 of the city's most thickly barangays are in areas most prone to earthquake damage and landslides magnifies Baguio's risks.

An unbelievable population density of 58,974 people per sq km is also found in Upper Magsaysay, where there is a sinkhole that has already caused a bus terminal and a small hotel to crumble a year apart of each other.

A sinkhole is an underground vacuum that develops in limestone areas or places that are soluble to rainwater. As water seeps into the limestone, a vacuum is gradually created that then slowly sucks in the topsoil. It is only a matter of time until the ground above gives way.

Sinkholes are quite common in Baguio City, which also has at least seven known faults and numerous areas vulnerable to landslides. Landslides could be triggered by an earthquake or continuous rainfall, which can also cause sinkholes to wreak havoc. Because Baguio has one of the 10 highest daily rainfall records in the world and is visited by an average of five cyclones in a three-year period, landslides and sinkhole-related mishaps are givens.

This and the presence of the faults—cracks or gaps in geological plates, the sudden movement of which causes earthquakes—are most probably why the World Bank lists Baguio as among the top seven risk-prone cities in Asia. But while Baguio officials are well aware of the delicate nature of their city, little has been done to discourage people from constructing homes and even buildings in areas where the ground is unstable.

In fact, after the sinkhole in Upper Magsaysay caused the collapse of the Rabbit Bus Terminal and Summit Inn Hotel in 1991 and 1992 respectively, the city council still issued a permit to rebuild the bus station in the same place.. It took a veto from the mayor to block the terminal's construction, but other commercial buildings and at least 30 squatter shanties now sit precariously along the sinkhole's edges. Visible cracks have been reported within the periphery but no effort has been made to close down the buildings and relocate residents.

Another sinkhole sucked in a residential building in 1996, this time at Crystal Cave barangay. The Department of Environment and Natural Resources (DENR) then issued a warning to relocate to some 50 other endangered buildings in the area. One underground inspection showed the barangay has 18 sinkholes, with diameters ranging from one to 225 meters.

Most of the structures there have no building permits and belong to squatters. Some were even within the Crystal Cave watershed reservation. But up to now, the local government remains reluctant to force them out of the high-risk area. Reasons Baguio Mayor Mauricio Domogan: "If we demolish them, they will accuse us of being anti-poor. Whether you like or not, even if your intentions are for their own well being, they will file cases in court and we will end up being the villain here."

Some observers say the fact that no one was hurt in the Crystal Cave incident and that a total of "just" two died when the bus terminal and the Summit Inn Hotel collapsed could help explain City Hall's seeming lack of urgency in ridding sinkhole-ridden areas of residents. But the local government is as slow in emptying landslide-prone places of people, despite the surfeit of examples here and elsewhere that show just how deadly landslides can be.

In fairness, it has not been easy to convince residents of decades-old communities to abandon their homes even after these were discovered to be in areas with faults running through them or had a high slope failure potential. Yet many say City Hall has no excuse in making places with known similar hazards as squatter relocation sites, as has been done to Quirino Hill and the Holy Ghost. Quirino Hill is also known to be sitting on top of a sinkhole.

Today, there are even fears that City Hall would invite high-density activities into other hazardous areas. Observers say such an aim is contained in a proposed new comprehensive land use plan that has been drafted by the City Planning and Development Office.

Generally, the plan attempts to disperse the population from Baguio's overcrowded central business district by introducing "growth nodes" or commercial areas in the city's outskirts. The problem, say many observers, is that these growth nodes are also in high-risk areas.

Irisan barangay, for example, has been identified as a growth node for high-density commercial activities owing to its access to Naguilian Road. But the area has been classified having a high slope failure potential and therefore landslide-prone. Its limestone foundation also makes it vulnerable to the formation of sinkholes.

Another growth node, Bakakeng-Dontogan-Sto.Tomas, has been pinpointed as a site for medium-scale commercial activities. Sto. Tomas, besides having the Mirador fault (maximum potential magnitude: intensity 7; the 1990 quake was intensity 7.7), is classified as with a high slope failure potential, similar to Dontogan. The Bakakeng area has a similar classification, aside from being exceptionally earthquake-prone. Two faults cross Bakakeng - the Mirador and the San Vicente, which has been exhibiting surface manifestation of late.

Assistant City Planning and Development Officer Art Orig defends the land use blueprint by saying that "mitigation plans"—from good site designs to land management practices such as locating roads parallel to slopes rather than cutting through them—will be in place to ensure the safety of the population.

He also says, "There are those who are against the development of growth nodes because of the environmental hazards in them. We know where these hazards are and, given enough time to explain, we could tell them how good planning and proper building practices could mitigate its effects."

That the plan has attracted many critics, however, can be traced partly to what has been found out so far about Baguio's urban planning and building practices.

European urban planners who inspected five buildings damaged during the 1990 earthquake, for instance, noted how improper siting and construction practices in Baguio increase the risk of damages during natural calamities. These include the use of small, rounded river pebbles as aggregates, insertion of water pipes inside columns, situation of building near steep slopes and non-symmetrical building shapes due to site restrictions.

In addition, City Councilor Elmer Datuin points out that even a routine inspection of boarding houses to safeguard Baguio's huge student population, is often not done at all because of a shortage in manpower. The dearth in equipment, meanwhile, has been blamed for the lack of geological tests before any construction begins. As a result, weak geological foundations are sometimes discovered only after unexplainable cracks appear in a building already in use.

For almost six years, some 300 students attended classes in an annex of the Baguio City National High School before the building was found to be atop an underground spring and against an unstable vertical soil excavation. It was only early this year, when school officials noticed water seeping through cracks in the annex's ground floor, that an inspection of the ground on which the building stands was made.

Tests still have to be conducted to determine whether or not the annex can be saved. But not one among the City Engineer's Office, the DENR and even the local office of the Department of Public Works and Highways (DPWH) has the equipment to do the necessary ground boring tests.

School Principal Elma Donaal dreads to think of what could have happened had the ground given way while classes were going on in the annex. She asks, "How could a public building be constructed without first checking whether the soil is strong enough to hold it?"

In the case of the sunk building at Crystal Cave, the inspection that led to the discovery of the area's many sinkholes was done only at the insistence of residents who initially believed an underground blasting done by the city government had caused the accident. Because of the forced inspection, officials concluded that the building sank due to a sinkhole underneath it. But geologist Trixie Concepcion, who was hired by Crystal Cave residents, says the blasting was nevertheless "ill-advised owing to its disregard of the rock formation."

The blasting had been done to create a sewage canal that would declog a nearby lagoon. But Concepcion hints that the activity should not have been considered in the area at all. She also says, "The maps presented by the engineers of the project show that it (was) poorly done and possibly without thorough groundwork."

"Maybe these improper practices could be corrected," says a city official critical of the proposed land use plan. "But I think it is too late given the high population of Baguio today. It seems that city planners are only trying to lessen the possible effects of these dangerous areas rather than totally avoiding them."

In truth, city planners are hard pressed in finding space for all who want to live in Baguio. The city already has a population growth rate of 4.1 percent - nearly twice the national average and almost thrice that of the Cordillera region.

With a land area of only 5,750 hectares, this growth rate has crammed people by 5,525 per sq km, according to the latest projection of the National Statistical Coordination Board. This translates to a population density that is 1,500 percent higher than the national average, and which some urban planners say beats that found in most of the world's other "seismic areas."

This was not always the case. But in the past few decades, Baguio has seen a steep climb in the number of migrants looking for work to the city, many of whom inevitably stay and raise families here. According to official figures, migrants now make up 40 percent of Baguio's current population.

"People are naturally attracted to Baguio because of its cool climate and because it is the administrative, service and trade center in the Cordilleras," says Mayor Domogan. But he also admits that the high in-migration rate is largely to blame for the city's rising squatter population.

Still, it is also Baguio's apparent hospitality toward squatters that has helped attract even more migrants to the city - and made the occupation of even the most hazardous areas inevitable.

A paper by University of the Philippines-Baguio professor Rowena Reyes-Boquiren indicates that when it comes to managing the squatter problem, the city's history has been one of accommodation.

She says the attempt to institutionalize squatting in Baguio began in the 1950s, when the Baguio Workingmen's Village at Aurora Hill was made a relocation site. In 1967, as squatters continued to proliferate, the government issued Proclamation 232 declaring Holy Ghost Extension, Rock Quarry, Kennon-Hillside, Quirino Hill and Pinsao Pilot Project as additional relocation sites.

Writes Reyes-Boquiren: "Instead of lessening the city's squatting problem, Proclamation No. 232 became a means for politicians to promote their vested interests during elections in the 1970s. The scramble for land among favored supporters resulted in overlapping claims among squatters and their influential patrons from the ranks of politicians, government officials and employees."

But the migrants kept on coming. At least 80 proclamations originally reserved 93.26 percent of Baguio's total land area, or 5,362.48 hectares, for national government use. Reyes-Boquiren says these reserved spaces dwindled to 1,912.48 hectares as the need for more residential areas increased. Today, much of what has been left as reservations has been overrun by squatters.

Yet if city officials are considering high-density activities in areas they know to be dangerous, it is also because Baguio residents have become open to living in places that are geologically unsound. The lack of available land has apparently made many desperate. Comments a city official: "If there is somebody insane enough to give up his property, there will always be someone else more insane to squat on that property."