We all know how much damage Supertyphoon Yolanda (international: Haiyan) brought to the Philippines back in November 2013. For instance, devastating storm surges wreaked havoc in many places where Yolanda made landfall, most notably in the coastal areas of Samar and Leyte. https://www.youtube.com/watch?v=rS0gv4Xbw7w But one surprising aspect of Supertyphoon Yolanda that hasn't been widely discussed is... Continue Reading →
Update: Mayon satellite observation
A bit of a good news on Mayon: PHIVOLCS has lowered the alert level to Alert Level 3. Hopefully, things will go back to normal and all those affected will be able to go back to their homes. In the meantime, here are two of the latest satellite images of Mayon from Sentinel 2 since... Continue Reading →
What are debris flows?
Last time, I mentioned that what hit Mocoa, Colombia were not floods or mudflows, but debris flows. But what exactly is a "debris flow?" This term isn't very well-known, at least in popular usage. Indeed, numerous reports describe the Mocoa tragedy as caused by either a mudflow, mudslide, or a landslide (which is technically correct,... Continue Reading →
Mayon Volcano lava flows
(Image above: False color composite generated from Sentinel-2 data draped over Google Earth terrain) Although I've been to several volcanoes and have studied and worked on volcanic deposits before, this is the first time I've seen an eruption in person. I posted photos from our trip to Mayon, where we tried to document the eruption,... Continue Reading →
Mayon Volcano
Mayon Volcano, the most active volcano in the Philippines, is erupting again. The activity started last January, and it's still continuing until now. Eruption types have ranged from Strombolian to Vulcanian. The volcano is continuously degassing, with some occasional lava fountaining. Here are some photos I took when got a chance to go there.
InSAR image of the Mw 6.4 2018 Taiwan earthquake
Last week, a deadly Mw 6.4 earthquake struck Hualien, Taiwan, killing dozens of people. The image is an interferogram processed from two descending . Sentinel 1 images dated February 5 and 11, 2018 using SNAP. The focal mechanism solutions are from the GEOFON Program. Take note that these are preliminary results, no additional corrections were... Continue Reading →
Deformation in Mt. Agung, Indonesia detected by Sentinel-1
Mt. Agung, a volcano in Bali, Indonesia, has been experiencing unrest lately, and Indonesian officials fear that an eruption might be imminent, prompting thousands to flee. This is a differential interferogram generated from a pair of Sentinel-1 SAR imagery dated 28 August and 21 September 2017 downloaded from the Sentinel Data Hub and processed using... Continue Reading →
Mining flood height data from social media
I think we can all agree that social media is a gold mine of data; one particularly underutilized area is extracting hazards-related data and making it useful for analysis. Last September 12, two typhoons almost simultaneously crossed the Philippines bringing heavy rains in many parts of the country. This caused floods in many different areas.... Continue Reading →
Dangerous debris flows
A little over a month ago, heavy and sustained rainfall in Mocoa, Colombia triggered deadly landslides and debris flows, claiming more than 300 lives. Post-event analysis by scientists from GFZ Potsdam show that more than 600 landslides occurred within the watersheds next to town. The mixture of soil, rocks and debris from the landslides mixed with water... Continue Reading →
Bohol fault-finding
Photo above: At Inabanga, Bohol, where the ground rose about 3 meters. If you look closely, there's a person among the rubble, for scale. The 2013 Bohol earthquake was one of the Philippines' biggest earthquakes in recent history. It was a terrible disaster; killing a lot of people and damaging millions of pesos worth of properties. What's... Continue Reading →