745 aftershocks recorded
The Philippine Institute of Volcanology and Seismology (Phivolcs) has so far recorded over 700 aftershocks following the magnitude-six earthquake that struck Compostela, Davao de Oro on Wednesday, Feb. 1.
Phivolcs has detected 745 aftershocks as of 8 a.m., Friday, Feb. 3, with magnitudes ranging from 1.3 to 3.6.
Of the recorded earthquakes, 70 earthquakes have been plotted by three or more stations while only one tremor was felt.
The epicenter of the magnitude-six earthquake which occurred at 6:44 p.m. was located two kilometers southwest of Compostela, Davao de Oro and had an estimated depth of 17 kilometers.
According to Phivolcs, “strong to great” earthquakes have affected Davao de Oro and neighboring areas in the past.
“At least nine strong to great earthquakes ranging from magnitude 6.0 to 8.3 occurred in Davao de Oro and vicinity from 1891 to present based on the SEASEE Report and Phivolcs Earthquake Catalog,” Phivolcs said.
“The most damaging earthquake that affected Davao de Oro was the 21 June 1893 magnitude 7.3 Monkayo earthquake along the Philippine Fault, which produced numerous landslides, liquefaction impacts, and structural damages. This earthquake generated long and wide cracks that may be attributed to a surface rupture along the Central Compostela Valley segment of the Philippine Fault. Based on historical accounts, the earthquake was felt at a maximum intensity of VII (Destructive) in
Monkayo,” it added.
‘Amihan’ persists
The cold air from the northeast monsoon or "amihan" continues to be experienced in large parts of Luzon and Visayas although it is relatively weak compared to the previous weeks, said a weather specialist of the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA).
“Sa mga nagtatanong kung simula na ito ng tag-init o warm dry season sa ating bansa, ang sagot po natin ay hindi pa (To those who are asking if this is the beginning of summer or warm, dry season in our country, our answer is not yet),” Benison Estareja said on Friday, Feb. 3.
“Makakaranas pa rin tayo ng mga pagbugso ng amihan hanggang matapos ang Pebrero dito sa malaking bahagi ng Luzon, as well as Eastern Visayas habang sa unang bahagi ng Marso ay meron pa rin tayong amihan lalo na sa may Northern and Central Luzon (We will still experience surges of northeast monsoon until the end of February in large parts of Luzon, as well as in Eastern Visayas, while in early March, we still have surges of northeast monsoon, especially in Northern and Central Luzon),” he added.
Estareja said the northeast monsoon will continue to temporarily weaken in the coming days before another surge by mid-February.
PAGASA defines amihan as cold winds from the northeast that bring rains over the eastern side of the country. It also records the coldest day of the year during the northeast monsoon season.