The M6.7 earthquake (Figure 1) that struck Surigao City on 10 February 2017 caused a 2D shift in the coordinates by as much as 12.9 cm in the north-west direction (Figure 2). This displacement (10.1 cm to North, 8.0 cm to West, and 2.8 cm Down) (Figures 3, 4, and 5, respectively) was measured from 09 to 11 February 2017 from the active geodetic station (AGS) PSUR of PageNET, which is located in Surigao City, 14km from the earthquake’s epicenter. The next nearest AGS PTGO in Tagoloan, Misamis Oriental, which is 158 km from the epicenter, showed no significant shift in its position.
The data from PSUR was processed using Bernese GNSS Software from 01 to 20 February 2017 (10 days before and after the event) using the best available products (e.g. orbits, clocks) from the International GNSS Service (IGS). The displacements measured are not fixed to a stable tectonic plate and are just based solely on the change in position in the ITRF. The reference coordinates of the stations are based on the May 2015 monthly solution from Bernese.
Continuous monitoring of the stations is ongoing for post-earthquake events.
Coordinates in the International Terrestrial Reference Frame (ITRF) 2008
Global Navigation Satellite System
1. Date format: dd.mm.yy, e.g. 1.02.17 = 1 February 2017
2. Each data point corresponds to one daily solution processed from Bernese
3. Displacements measured is difference of each daily coordinates from PageNET AGS’
reference ITRF2008 coordinates (epoch 15 May 2015). For example, in Figure 3, PSUR
Northing has moved ~0.04 m (N) on 29 January 2017 from its 15 May 2015 coordinates.
Readers can email email@example.com or fax letters to +63-2 884-2855 for their comments and suggestions.