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03. Science and Technology (Natural Sciences) Committee

Permanent URI for this communityhttps://repository.unesco.gov.ph/handle/123456789/3

In creating a culture of peace and addressing sustainable development challenges, UNESCO aims to cultivate the generation and application of scientific knowledge among its Member States. At UNACOM, we facilitate access to UNESCO’s international programmes in the sciences, such as the Intergovernmental Oceanographic Commission (IOC), Man and the Biosphere (MAB) Programme, and International Geoscience and Geoparks Programme (IGGP), among others.

Through this sector, the Commission aims to contribute to the following SDGs: 11 - Sustainable Cities and Communities, 13 - Climate Action, 14 - Life Below Water, and 15 - Life On Land. With the overarching vision of the 2023-2028 Philippine Development Plan (PDP), UNACOM targets grassroots-inspired cultural heritage and biodiversity protection and conservation, as well as multi-stakeholder partnerships for SDGs promotion.

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AGROVOC Keyword: search.filters.agrovoc.earthquakesAuthor: search.filters.author.Siringan, Fernando P.

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    Ground deformation analysis caused by post-2013 earthquake in Bohol, Philippines
    Bauzon, Ma. Divina Angela I.; Reyes, Rosalie B.; Blanco, Ariel C.; Siringan, Fernando P. (Springer Science and Business Media LLC, 2022-08-16)
    After the 2013 Mw 7.2 earthquake that occurred in Bohol, the shoreline specifically in Loon and Maribojoc was observed to shift seaward due to ground uplift. This study analyzes the post-earthquake shoreline movement, specifically a 12 km coastal strip in Loon and Maribojoc, and ground deformation of the West Bohol area through Sentinel-1 image processing techniques. From October 2014 to April 2018, the DSAS linear regression shoreline rates were − 4.36 m/yr in Loon and − 1.69 m/yr in Maribojoc, indicative of a landward movement of 91.4% and 88.8% of shoreline transects in Loon and Maribojoc, respectively. PSInSAR revealed varying rates of VLM in the study area from October 2014 to December 2018 such that Loon and Maribojoc exhibit a subsidence rate of − 2 to − 8 mm/yr. The correlation between the shoreline retreat and the land subsidence in the study area is 87%, indicating a possible elastic rebound after the earthquake. The portion of Tagbilaran City on its northern side exhibits land subsidence of − 2 to − 6 mm/yr while its southern side exhibits land uplift of 0–2 mm/yr. The relative sea level fall from TGSL measurements indicates an uplift in the location of the tide gauge in Tagbilaran City.
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    Shallow structures, interactions, and recurrent vertical motions of active faults in Lingayen Gulf, Philippines
    Flores, Paul Caesar M.; Siringan, Fernando P.; Mateo, Zenon Richard P.; Marfito, Bryan J.; Sarmiento, Keanu Jershon S.; Abigania, Maria Isabel T.; Daag, Arturo S.; Maac-Aguilar, Yolanda (Elsevier, 2023-06-01)
    The surface trace of the East Zambales Fault (EZF) and its associated faults in the Lingayen Gulf have been previously mapped but no other characteristics were reported. This study utilized seismic reflection, multi-beam bathymetry, and side scan sonar to characterize the offshore EZF in terms of magnitudes of vertical displacement. Sequence stratigraphy and radiocarbon dates provided age constraints on the recurrence interval within the Holocene. The EZF extends for ∼ 57 km into the gulf, follows a north-northwest trend, and bounds the karstic terrane (west) and fluvio-deltaic deposits (east). Sinistral motion is indicated by: 1) normal and reverse drag geometries, 2) reversal in the sense of throw with depth, 3) flower structure, and 4) right-stepping and the uplift of a pressure ridge named Pudoc Bathymetric High. The Central Lingayen Gulf Fault (CLGF), to the east of EZF, follows the same trend. The Lingayen Gulf Transverse Fault (LGTF), oriented east–west, forms a flower structure with the CLGF. The EZF, CLGF, and LGTF combined form the Lingayen Gulf Fault System, which divides the gulf into five fault blocks where uplift and subsidence locally occurred. A paleo-delta at −60 m yielded an age of 6.8 kyBP, indicating it was formed during the first Holocene highstand. With natural compaction considered, fault-associated subsidence of 46–53 m may have occurred. The average Holocene vertical displacement is 2.1–2.2 m, which translates to a recurrence interval of 320–270 years for the fault system. The faults can likely generate earthquakes with magnitudes 7.5 (EZF), 6.7 (CLGF), and 6.6 (LGTF).