Friday, September 23, 2016
Volcanism of the Philippines
The Philippines is a very volcanic island nation. There are between 23-53 active volcanoes at any time, another 30 potentially active volcanoes, and hundreds of inactive ones, and those are just the ones above sea-level. The eruptions of the volcanoes of the Philippines have been some of the most deadly and costly, having a great number of volcanic eruptions causing tsunamis and lahars. There are two major North-South volcanic arcs, one in Luzon, and one in Mindanao. At the moment, the six most active volcanoes in the Philippines are: Taal, Mayon, Bulusan, Hibok-Hibok, Pinatubo and Kanlaon.
(map from PHIVOLCS)
PHIVOLCS (The Philippine Institute of Volcanology and Seismology) has been praised with being responsible for saving the most lives from volcano-related disasters in the Philippines. Before the 1951 eruption at Hibok-Hibok, which killed 3,000 people, there was no government agency in charge of dealing with volcanoes.
(photo from Hibok-hibokrocks.blogspot)
Today PHIVOLCS have a great site that has lists of active, potentially active, and inactive volcanoes. They include a series of definitions of volcano related phenomena (both direct and indirect), such as lahars, pyroclastic blasts, and tsunami-generation. They have several volcano monitoring stations (see my post on September 9, 2016, with a map of where these are). They monitor volcanoes through four main strategies: a seismic network, a ground deformation network, hot-spring temperature and flow-rate measurements, and visual observation.
PHIVOLCS uses a 0-5 Volcano alert system, where O means no alert/or quiet, and 5 means hazardous eruption in progress. They issue warnings for no fly zones in ares with high ash, as volcanic ash can damage airplane engines. They issue evacuation warnings and establish safety perimeters (from 4-9 kilometers depending on alert level between 1-4), they also issue warnings for ash fall in residential and farming areas. They are responsible for issuing warnings for riverside communities that could be affected by ash contamination in the water downstream of volcanoes, especially following periods of heavy rainfall.
(photo from Newhall, USGS)
The most recent eruption was on September 16, a 4-minute long phreatic (steam-blast) eruption at the Bulusan Volcano on the southeastern part of the island of Luzon (250 km from Manila). Bulusan regularly erupts these steam-blasts, which eject steam and ash into the air. Although some of the blasts are of short duration, the ash can be carried by the wind to nearby towns and water sources. Bulusan is a strato-volcano so people in the area take precautions because an eruption of Mount Bulusan could be highly explosive. Bulusan Volcano Natural Park surrounds the volcano, but there are evacuation procedures for nearby farms and PHIVOLCS establishes and adjusts the threat level as they evaluate the volcano. The alert level for Bulusan is currently 1, which means there is a low level of volcanic unrest. There is currently a four-kilometer Permanent Danger Zone around the volcano, and the area directly over the volcano is considered a no-fly zone during periods of any visible activity.
References: http://volcano.si.edu/reports_weekly.cfm#vn_273010, http://www.phivolcs.dost.gov.ph/index.php?option=com_content&view=article&id=50&Itemid=86, https://www.volcanodiscovery.com/philippines.html, http://hibok-hibokrocks.blogspot.com/2011/12/time-magazine-article-december-1951-mt.html, http://geographic.org/photos/volcanoes/volcano_photos_314.html
Monday, September 12, 2016
Seismicity Map of the Philippines
This is a follow-up from my post on Friday, to include this awesome map and some recent data.
This map of the distribution of active faults and trenches in the Philippines clearly shows the convergence zones off both the East and West coasts of the country, crossing onto land only on the island of Mindoro. There is a collision zone mostly near the western waters of Panay, but also crossing over the southwest tip of the island. There is also a transform boundary to the northeast of Pulong Polillo in the Philippine Sea. As you can see from the map there are a multitude of faults ranging through most of the islands, the notable exception is Palawan in the West.
From the good folks at PHIVOLCS:
Recent activity from IRIS: Since September 1st of this year, there have been 9 significant earthquakes in the southern region of Mindanao, ranging from M4.6 to M5.9. The most recent was at 16:29 UTC, on September 10, 2016, a M5.3.
References: http://www.phivolcs.dost.gov.ph/, http://ds.iris.edu/seismon/eventlist/index.phtml?region=Polynesia
This map of the distribution of active faults and trenches in the Philippines clearly shows the convergence zones off both the East and West coasts of the country, crossing onto land only on the island of Mindoro. There is a collision zone mostly near the western waters of Panay, but also crossing over the southwest tip of the island. There is also a transform boundary to the northeast of Pulong Polillo in the Philippine Sea. As you can see from the map there are a multitude of faults ranging through most of the islands, the notable exception is Palawan in the West.
From the good folks at PHIVOLCS:
References: http://www.phivolcs.dost.gov.ph/, http://ds.iris.edu/seismon/eventlist/index.phtml?region=Polynesia
Friday, September 9, 2016
Earthquake Mitigation Strategies in the Philippines
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) is the Philippine equivalent of the USGS, and has established some innovative earthquake risk reduction projects in the Philippines.
In collaboration with Japan, PHIVOLCS has conducted structural integrity studies of concrete hollow block houses, one of the main building types of residential dwellings in the Philippines. They have developed a self-check for earthquake safety entitled "How Safe is Your House" that addresses vulnerability of houses based multiple factors, that allows people to evaluate the potential integrity of their own home.
One of their culturally-inspired projects was Handa...Awit...Lindol! (Ready...Sing...Earthquake!), a collection of (Karaoke-style) songs for preparedness for earthquakes and natural hazards. Since singing is a national pastime, this creative University of the Philippines Diliman funded project incorporates hazard education and music. Check out the "Pacific Ring of Fire" song, the "Intensity" song that describes the differences between the magnitudes of earthquakes, or the rock/rap style "Don't Panic" song that tells you what to have in your emergency kit! (https://soundcloud.com/up-diliman-ovcrd/sets/handa-awit-lindol)
PHIVOLCS also offers a series of hazard maps, for faults and trenches, earthquakes, earthquake-induced landslides, liquefaction susceptibility, tsunami, and volcanoes.
According to PHIVOLCS:
(Map from PHIVOLCS.dost.gov. ph)
The Philippines coordinates with the Global Seismographic Network, and they have shared data from their Davao station since 1994. The broadband connection from the station operated by PHIVOLCS, updates the data to the global network about every 10 minutes.
References: http://www.phivolcs.dost.gov.ph/images/CHB_Test_Briefing_3_0001.mp4, http://www.phivolcs.dost.gov.ph/images/Flyer-How-Safe-Is-Your-House.pdf, https://soundcloud.com/up-diliman-ovcrd/sets/handa-awit-lindol, http://www.phivolcs.dost.gov.ph/index.php?option=com_content&view=article&id=44&Itemid=300083, http://earthquake.usgs.gov/monitoring/gsn/, http://earthquake.usgs.gov/monitoring/operations/station.php?network=IU&station=DAV,
In collaboration with Japan, PHIVOLCS has conducted structural integrity studies of concrete hollow block houses, one of the main building types of residential dwellings in the Philippines. They have developed a self-check for earthquake safety entitled "How Safe is Your House" that addresses vulnerability of houses based multiple factors, that allows people to evaluate the potential integrity of their own home.
One of their culturally-inspired projects was Handa...Awit...Lindol! (Ready...Sing...Earthquake!), a collection of (Karaoke-style) songs for preparedness for earthquakes and natural hazards. Since singing is a national pastime, this creative University of the Philippines Diliman funded project incorporates hazard education and music. Check out the "Pacific Ring of Fire" song, the "Intensity" song that describes the differences between the magnitudes of earthquakes, or the rock/rap style "Don't Panic" song that tells you what to have in your emergency kit! (https://soundcloud.com/up-diliman-ovcrd/sets/handa-awit-lindol)
PHIVOLCS also offers a series of hazard maps, for faults and trenches, earthquakes, earthquake-induced landslides, liquefaction susceptibility, tsunami, and volcanoes.
According to PHIVOLCS:
"The Philippines has a total of 65 seismic stations, 29 of which are manned, 30 are unmanned, and 6 volcano stations. The central operating station is located at PHIVOLCS Main Office, Diliman, Quezon City. All information is received at the Data Receiving Center (DRC), which is operated 24/7 by the Seismological Observation and Prediction Division (SOEPD)." (PHIVOLCS)
(Map from PHIVOLCS.dost.gov. ph)
The Philippines coordinates with the Global Seismographic Network, and they have shared data from their Davao station since 1994. The broadband connection from the station operated by PHIVOLCS, updates the data to the global network about every 10 minutes.
References: http://www.phivolcs.dost.gov.ph/images/CHB_Test_Briefing_3_0001.mp4, http://www.phivolcs.dost.gov.ph/images/Flyer-How-Safe-Is-Your-House.pdf, https://soundcloud.com/up-diliman-ovcrd/sets/handa-awit-lindol, http://www.phivolcs.dost.gov.ph/index.php?option=com_content&view=article&id=44&Itemid=300083, http://earthquake.usgs.gov/monitoring/gsn/, http://earthquake.usgs.gov/monitoring/operations/station.php?network=IU&station=DAV,
Saturday, September 3, 2016
The Philippines
The Philippines is a Southeast Asian island nation located at 13 00 N, 122 00 E. The Philippine North-South archipelago includes
over 7100 islands. The lowest elevation is at sea-level, while the highest elevation is Mount
Apo at 2,954 meters. The country is divided into three main regions, the northern Luzon, the central Visayas, and the southern Mindanao. The northern island of Luzon, houses the capital
city, Manila.
(Map and flag from CIA.gov)
To say the Philippines is located in an active tectonic region is putting it mildly. You can see on the USGS map below the Philippine Sea Plate borders the island nation to the East, subducting under the Sunda Plate, while the Eurasian Plate is subducting under the west coast of Luzon.
"The 1,200-km-long Philippine fault zone (PFZ) is a major tectonic feature that transects the whole Philippine archipelago from northwestern Luzon to southeastern Mindanao. This arc-parallel, left-lateral strike slip fault is divided into several segments and has been the source of large-magnitude earthquakes in recent years." (The Philippine Institute of Volcanology and Seismology)
Earthquakes and volcanoes are a part of life in the Philippines, as well as tsunamis, typhoons, flooding and landslides.
(Map from USGS)
References: http://www.gov.ph/, https://www.cia.gov/library/publications/the-world-factbook/geos/rp.html, http://pubs.usgs.gov/of/2010/1083/m/, http://www.phivolcs.dost.gov.ph/
(Map and flag from CIA.gov)
To say the Philippines is located in an active tectonic region is putting it mildly. You can see on the USGS map below the Philippine Sea Plate borders the island nation to the East, subducting under the Sunda Plate, while the Eurasian Plate is subducting under the west coast of Luzon.
"The 1,200-km-long Philippine fault zone (PFZ) is a major tectonic feature that transects the whole Philippine archipelago from northwestern Luzon to southeastern Mindanao. This arc-parallel, left-lateral strike slip fault is divided into several segments and has been the source of large-magnitude earthquakes in recent years." (The Philippine Institute of Volcanology and Seismology)
Earthquakes and volcanoes are a part of life in the Philippines, as well as tsunamis, typhoons, flooding and landslides.
(Map from USGS)
References: http://www.gov.ph/, https://www.cia.gov/library/publications/the-world-factbook/geos/rp.html, http://pubs.usgs.gov/of/2010/1083/m/, http://www.phivolcs.dost.gov.ph/
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