Is Calbayog City safe from tsunami because it does not face the Pacific Ocean and there are islands that can block the upsurge?
The Department of Science and Technology-Philippine Institute of Volcanology and Seismology resident geologist Jeffrey S. Perez says “no,” debunking the belief that this city in Eastern Samar is free from the effects of any seismic activity within and outside the province, especially tsunamis.
In his presentation on the overview on geological hazards and warning systems at the recent Science for Resilient Business and Government Services Seminar-Workshop at Calbayog City Convention Center recently, Perez advised the Samar-based participants to be always prepared for any disaster, especially earthquakes and tsunamis that can possibly hit the province.
For many years now, the residents of Calbayog City have thought they are safe from the severe aftermath of disasters as the city lies on the west side of Samar, away from the Pacific Ocean. But Perez reiterated the possibilities of earthquakes, volcanic eruptions, and tsunamis hitting the city, based on the historical records of seismic activities of Region VIII.
The people also had the belief that since there are three islands at the Samar Sea, namely Sto. Nino, Tagapul-an, and Almagro, that are “blocking and protecting” their city from the Pacific Ocean, it is impossible for a tsunami to hit them.
“Just because you are located away from the Pacific Ocean and there are islands in front of you does not necessarily mean that no tsunami will reach you. Historically, your side of the province, including Calbayog, has already experienced tsunami before,” Perez stressed.
The Philippines is prone to numerous natural hazards due to its geologic and geographic setting, and Calbayog City and the whole Region VIII are not exempted.
According to Perez, there are a few active faults, volcanoes and trenches around Calbayog City. The nearest active fault in fact is 10.5 kilometers away from the city.
From 1975-2013, 14 damaging earthquakes, one every three years, have already struck different provinces in Region VIII. Meanwhile, three of these earthquakes, including one in 1925, with average magnitude of 7.0 to 7.6, have caused one to two meters of tsunami.
Moreover, a historical record in 1960 showed that during the magnitude 9.5 “great earthquake” in Chile, which is 24 hours away from the country, tsunami reached the Eastern Philippine shores 24-26 hours after the disaster.
In the eastern shoreline of Samar Island, eyewitnesses reported that the tsunami that reached them has a height of 6 meters, while the tsunami waves that reached Tacloban, Leyte has a height of one meter, based on tight gauge records. If these waves have reached Leyte, there is a big possibility that Calbayog was also affected during that time.
Perez also mentioned that Calbayog folks should disregard their belief that the islands in front of them will spare them from tsunamis because these very islands can even worsen the situation.
“Although there are islands blocking you from the ocean, the tsunami waves will only go around it and may even become bigger when it gets to you. And remember that tsunami waves from the West Philippine Sea can also affect you,” Perez added.