‘Earth wall’ rises
INABANGA, Bohol – It’s harvest time for rice farmers in barangay Anonang but instead of going to their fields, villagers stand around in groups, awed by a strange sight.
The Oct. 15 earthquake pushed up a “wall” three meters high in some sections, spanning as far as the eye can see.
“Residents are afraid to go out. Some farms are really cut up,” said barangay captain Felix Caray in Bisaya.
Some farms were split into two, with portions at a lower or higher elevation than the other half.
The massive land movement is being studied as a new Bohol fault line that caused the 7.2 magnitude earthquake that shook Central Visayas.
“Yung na talaga ang dahilan (That is really the cause),” said government geologist Dr. Alfredo Mahar Lagmay, who arrived with his team on Monday to survey the area.
“When the displacement of land is that height, that’s comparable to a magnitude 7.2 quake,” he told Cebu Daily News.
The newly-discovered fault is about 20 kilometers away from the East Bohol fault and appears to stretch north-northeast to southwest from Inabanga, Bohol to the near shore area of southeast Cebu in Boljoon town, said Lagmay based on historical data of earth movements from the epicenter since Oct. 15.
The fault could be more than 12 kilometers deep and more than 100 kilometers long, said Lagmay.
The visible ground rupture “spans several kilometers from Inabanga to Catigbian town. We’re now assessing exactly how long the fault is,” he said.
Lagmay, who has a Ph.D in geology from the University of Cambridge, is executive director of Project NOAH of the Dept. of Science and Technology.
Since the ground rupture is too vast to cover on foot, they will scan it from a plane using a “lidar,” a remote sensing technology that measures distance with a laser and analyzing the reflected light. The term “lidar” comes from combining the words light and radar. The device is popularly used in making high resolution maps.
The topography survey will be used to identify areas susceptible to landslides and sinkholes.
The ground is still unstable, said Lagmay. The earthquake may have pulverized rocks and stones, shifting them to hollow portions underground , causing sinkholes.
While cracks are still fresh and visible, scientists can survey the area and advise what places should building houses be prohibited and other precautions.
The discovery of a “new” fault line in northwestern Bohol doesn’t mean quakes would be more frequent, said Lagmay, addressing fears of Boholanos.
It takes many years to gather energy of the level needed to cause an earthquake.
Lagmay said the Philippines has many fault lines. The longest is the Philippine fault line which runs from Aparri in Luzon to Mati in Mindanao. It would take several decades for a fault line to emerge.
Barangay Anonang’s 948 families evacuated their homes and are staying in open spaces in sitio Semangan and Saksak.
“I am never going near the cracks,” said farmer Dionesio Caray in Bisaya.
“The harvest may be laid to waste but I can’t afford to lose my life. My family depends on me for support.”
He said he was waiting for the ground to stabilize before he returns to his farm.
More than one family stays in each makeshift tent, usually waiting for relief aid to arrive.
Children were getting sick after exposure to the elements, especially on chilly nights.
Barangay captain Caray told government social workers, they need medicine for coughs and colds.
Signs that read: “We need food and water” are hung all over barangay Anonang and neighboring towns affected by the earthquake last week.
The fault line is visible in five out of seven sitios – Kalubian, Patag, Talisay, Komayot, and Centro.
Only motorcycles can pass through the road in sitio Kalubian since the ruptured ground crosses the road.
Motorists passing through are met by a ‘wall’ of earth about six feet high. Some trees were almost swallowed by the earth.
Residents, who worried that the village was “sinking” or a volcano was forming, were assured by a Phivolcs team, who briefed them Wednesday night it was a natural phenomenon for the earthquake to cause portions of the land to rise.
Despite the Phivolcs explanation, some anxious residents prefer to stay outside in canvass tents.
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