Imaging ground surface deformations in post-disaster settings via small UAVs

Geoscience Letters

Official Journal of the Asia Oceania Geosciences Society (AOGS)

Table 1 Summary of workplan information cited in Fig. 4 as applied to the different disaster events and their corresponding products

Event	Lag days*	Pre-deployment			On-site considerations					Flight parameters					Products
Event	Lag days*	Remotely-sensed data	Terrain and hazard maps	Local reports	Shapefiles	Accessibility and situational safety	Target features	Size of affected site (km²)	Size of deformed surface features	Dim. of flight plan (m²)	Elev. (m)	Overlap size (%)	Orien-tation	Flight time (min)	Reso-lution (cm)	Types
2019 Central Luzon earth-quake	1	–	IfSAR DTM	Escorted by local officials	Earthquake epicenter	Highly accessible and safe	Lateral spreading (Fig. 6)	3.6	Length: 40 m	8000	50	80	NE	5	1.17	Orthomosaic Point cloud DSM
				Affected residents			Lateral spreading (Fig. 6)		Vertical offset: 60 cm
							Road collapse (Fig. 7)	0.1	Length: 150 m	40,000	50	80	N	25	1.18
							Road collapse (Fig. 7)		Vertical collapse: 4 m
2019 Cotabato earth-quakes	7	Initially-processed InSAR products	IfSAR DTM	Escorted by local officials	Interpreted line from InSAR products	Damaged roads	Landslide (Fig. 8)	0.5	Area: 6000 m²	300,000	100	70	NE	18	4.78	Orthomosaic
		Raster images	Landslide hazard maps	Affected residents	Earthquake epicenters	Militant threat	Riedel shears (Fig. 9)	0.002	Lengths: 1–2 m	N/A (manual flight)	4	10–30	NE	10	0.11
						Landslide threat	Riedel shears (Fig. 9)		Area: 900 m²	N/A (manual flight)
2020 Taal eruption	12	–	LiDAR DTM	NDRRMC reports	Points from reports of reported fissures	Within 14 km danger zone	Fissures (Fig. 10)	1.8	Lengths: 1–19 m	135,000	100	60	NW	18	3.38	Orthomosaic
			Volcanic hazards maps	PHIVOLCS reports		Damaged roads
				Social media posts		Danger of eruption

*The number of days after the event that the survey team was deployed and data was acquired