By Jes Tirol
Decisions of our national officials are sometimes strange. Only recently President Arroyo declared June 11 as a holiday instead of June 12, which is the designated Independence Day. The official reason was to lengthen the "holidays."
If you will look at the 2007 calendar, Christmas and New Year also occur on Tuesdays.
If the same reasoning will be followed, then we will be told to celebrate Christmas on Monday December 24 and New Year on Monday December 31.
The Philippine National Oil Corporation (PNOC) has already determined that oil deposits exist underneath the Municipality of Clarin, Bohol. What I find to be strange is that the Department of Energy (DOE) will explore at the Bohol Strait. Why not explore at or around Clarin, Bohol?
Existence of Oil
When we had our training in seismic or earthquake engineering, we were brought to the main office of PNOC for a lecture how seismic waves were utilized in oil exploration. We were showed the location of oil deposits in the Philippines determined by seismic exploration.
As a Boholano, I was interested in the island of Bohol. I saw in the map prepared by PNOC that underneath Clarin, Bohol and its environs is an oil deposit.
Our lecturer told us that two (2) to three (3) kilometers underneath the land surface is a thin sheet of flowing oil. This oil has a tendency to be deposited in underground cracks made by geologic fault lines. If the gap is big, then the oil deposit will be large.
The Fault Lines
Part of this article is a map showing the geologic fault lines affecting Bohol. Shown also is the known location of the oil deposit and the area where the seismic survey will be done.
The Zulu-Negros-Cebu trench is a long fault line that starts from the Zulu Archipelago, then across Mindanao Sea and one branch passes through the Tañon Strait between Negros Island and Cebu Island. Near the southern tip of Cebu Island, it branches off between Cebu and Bohol and continue smack into Cebu City and northward.
The Cebu Island land mass is known in geology as a "horst" formation because it is extruded due to pressures from fault lines on both sides.
Another fault line starts from the Mindanao Sea or Mindanao Island and passes through the tip of Anda Peninsula and through Tagbilaran Strait and meet the Zulu-Cebu fault line at the Bohol Strait between Loon, Bohol and Argao, Cebu. These two fault lines form like a huge arrowhead or inverted "V."
The Bohol fault line has a lateral fault line. It starts offshore of Jagna, Bohol and towards the mountain and exits Bohol to join the Trans-Philippine Fault at the island of Leyte. The movement of this fault line caused the recent landslide at Mayana, Jagna.
The Bohol fault and its lateral fault "dip" or dives under the island of Bohol slanting towards northern Bohol. These fault lines are intercepted by another fault line starting from Cebu City and running towards the island of Leyte. It dips towards Bohol.
If these fault lines intersect the free flowing underground oil, it is understandable that the oil will be deposited somewhere beneath the Municipality of Clarin and its environs towards Inabanga and Sagbayan.
If you will look at the map presented herewith, it would seem strange why the survey will be done at a place that is relatively far from the known oil deposit. Why not conduct the survey at Clarin, Bohol and its environs?
Next issue, I would present my opinion why it is doubtful that natural gas will be found in Bohol Strait.(The Bohol Chronicle, June 17, 2007)
(to be continued....)