Philippine Standard Time

Poster March 2023 M5On March 2023, a series of moderate-magnitude earthquakes shook Davao de Oro and its vicinity. These earthquakes occurred on March 06, 04:43 a.m. Philippine Standard Time (PST) at magnitude (M) 5.3, and on March 07, 02:02 p.m. and 04:47 p.m. at magnitudes 5.9 and 5.6, respectively. The depths of these earthquakes range from 2 to 11 km. The M5.9 quake caused ground shaking that was felt at PHIVOLCS Earthquake Intensity Scale (PEIS) VI (very strong) in the municipalities of Maco, Maragusan, Mawab, Nabunturan, and New Bataan in Davao de Oro, and as far as South Upi in Maguindanao at PEIS I (scarcely perceptible). Based on the epicenters, focal mechanisms, and actual field observations, these earthquakes were generated by the Caraga River Segment of the Philippine Fault. The National Disaster Risk Reduction and Management Council (NDRRMC) reported 35 injured individuals, 2454 damaged houses, and 238 damaged infrastructures (NDRRMC Progress Report 09, 12 March 2023).

The DOST-PHIVOLCS Quick Response Team (QRT) was deployed from 08 to 24 March 2023 to: 1) conduct earthquake information, education and communication activities with local government units (LGUs) and local residents in the affected areas; 2) assess and map the earthquake’s geologic impacts and effects to structures; 3) deploy temporary seismic stations for accurate aftershocks monitoring; 4) conduct intensity assessment; and 5) assist the LGUs in assessing the selected evacuation/relocation sites in terms of earthquake hazards, if deemed necessary. The Seismological Observation and Earthquake Prediction Division (SOEPD) monitored the earthquake aftershocks, and an office support team assisted in data compilation and map generation during the field investigation.

Most of the damages to structures were sustained in Nabunturan, New Bataan, Maragusan, Maco and Mawab in Davao de Oro. Poor engineering practices and the use of substandard construction materials were the major contributing factors to the damages. Earthquake-induced landslides were documented in several barangays in Maragusan, Maco, New Bataan, Nabunturan and Mawab.


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