2006 Southern Leyte mudslide

A massive mudslide occurred on February 17, 2006 in the Philippine province of Southern Leyte that caused widespread damage and loss of life. The deadly landslide followed a ten-day period of heavy rains and a minor earthquake of magnitude 2.6 on the Richter scale. The official death toll stands at 1,126. [http://www.ifrc.org/cgi/pdf_appeals.pl?06/MDRPH00107.pdf "Philippine Landslide and Flood Operations Update #7"] , red, Red Cross, Appeal #MDRPH00107, update 7, 31 August 2007]

Overview

At about 10:30 in the morning on February 17, 2006, a cliff face of a ridge straddling the Philippine Fault collapsed in a combination rockslide-debris avalanche event, translocating and subsequently burying Guinsaugon village in the town of Saint Bernard. [http://www.sciencemag.org/cgi/content/summary/311/5769/1844?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=guinsaugon&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT "Disaster Relief: Too Late, Earth Scans Reveal the Power of a Killer Landslide"] , Science Magazine, 31 March 2006] Up to ten smaller landslides had occurred within the previous week in the vicinity of St. Bernard, but Guinsaugon was the worst-hit community.

Among the worst of the tragedies was the burial of the local elementary school, located nearest to the mountain ridge, as the landslide occurred when school was in session and full of children. Provincial Governor Rosette Lerias said at the time the school had 246 students and seven teachers; only a child and an adult was rescued immediately after the disaster transpired. About 80 women who participated in the celebration of the fifth anniversary of the Guinsaugon Women's Health Association were also lost in the avalanche. [http://www.inquirer.net/specialfeatures/leytelandslide/view.php?db=0&article=20060222-67012 "80 Abanse! Pinay members still missing in Guinsaugon"] , Philippine Daily Inquirer, 22 February 2006]

Lerias said that although several residents had left the area last week due to the fear of landslides, several of them had returned when the rains had eased.

Rescue and relief

Rescue teams including troops from the military were operating in the affected areas. However, relief efforts are hampered by rain, chest-deep mud, roads blocked by boulders, washed-out bridges, and lack of heavy equipment. A minor earthquake in the morning of February 17 also affected the relief operation as the ground remained unstable.

Philippine President Gloria Macapagal Arroyo made an address on television stating that "help is on the way". Navy and coast guard ships were dispatched to the coastal area. [http://www.alertnet.org/thenews/newsdesk/SP284666.htm "Hundreds feared dead in Philippine mudslide"] , Reuters, 17 February 2006]

On February 17, 2006, Philippine National Red Cross chairman Richard J. Gordon who was then in Geneva attending a boardmeeting of the International Red Cross and Red Crescent Movement appealed for international assistance.He raised US $1.5 million to help the victims of the mudslides. The funds will be used to purchase tents, blankets, cooking utensils, mosquito nets, temporary shelter materials, hygiene articles, water purification tablets and medicines. US $152,000 has already been released to provide initial assistance. A relief plane was being flown into the region carrying emergency trauma kits, rubber boots, ropes, clothing, flashlights and medicine. Three Philippines National Red Cross teams with search and rescue dogs were at the site to provide assistance and more are expected to join. [ [http://www.alertnet.org/thenews/newsdesk/L17729820.htm "Red Cross seeks $1.5 mln for Philippine mudslide"] , Reuters, 17 February 2006] The Red Cross said that it feared that the death toll would be high. [http://www.alertnet.org/thenews/newsdesk/SP284666.htm "Hundreds feared dead in Philippine mudslide"] , Reuters, 17 February 2006]

The United States sent two naval vessels, the USS "Essex" and the USS "Harpers Ferry" from the 31st Marine Expeditionary Unit, to the area to provide assistance. [http://www.alertnet.org/thenews/newsdesk/SP284666.htm "Hundreds feared dead in Philippine mudslide"] , Reuters, 17 February 2006] About 6,000 U.S. Army and Marine Corps troops are in the Philippines for an annual bilateral exercise. [http://pakistantimes.net/top021806010.htm No Signs of Life' after Huge Mudslide hits Philippines] , Pakistan Times] The US government has also donated $100,000 worth of disaster equipment to the Philippine Red Cross. USAID has turned over 2.9 million pesos (about $560,000) worth of food and non-food items. [http://news.inq7.net/nation/index.php?index=1&story_id=66625 Landslide triggers avalanche of international aid] , The Inquirer, 19 February 2006]

Other countries have donated or pledged assistance to the Philippine government. China offered a donation of $1 million in cash and material. Australia also offered AUS$1 million ($740,000) in immediate relief. Taiwan pledged enough medicine to treat 3,000 individuals for a month and a half along with $100,000. Thailand also pledged $100,000. Malaysia sent a 60-man search-and-rescue and medical assistance team named the Special Malaysia Disaster Assistance Team (SMART). Spain, through a non-government organization, the Unidad Canina de Rescate y Salvamento, sent a six-man rescue team equipped with five sniffer dogs to aid in the relief and rescue efforts. [http://news.inq7.net/nation/index.php?index=1&story_id=66625 Landslide triggers avalanche of international aid] , The Inquirer, 19 February 2006] . South Korea promised $1 million. New Zealand would send $133,000 to be used in future rescue operations. Singapore has said, according to a statement from Prime Minister Lee Hsien Loong, that officials would help the Arroyo administration in any way possible. Indonesia and Turkey have humanitarian contingents as well. Poverty striken countries also pitched in by lending $1 with a fixed interest rate of 150%p.a.

The Philippine Red Cross reported that 53 persons were rescued from the mud on February 17, but the rescue efforts had to be suspended at nightfall for safety reasons. [http://pakistantimes.net/top021806010.htm No Signs of Life' after Huge Mudslide hits Philippines] , Pakistan Times]

Possible causes

Philippine congressman Roger Mercado of Southern Leyte claimed in a Reuters interview that logging and mining done in the area three decades ago was the main culprit. [ [http://today.reuters.co.uk/news/newsArticle.aspx?type=topNews&storyID=2006-02-17T174324Z_01_MAN186309_RTRUKOC_0_UK-WEATHER-PHILIPPINES-LANDSLIDE.xml Hundreds feared dead in Philippine mudslide] , Reuters, 17 February 2006] Dave Petley, professor at the International Landslide Centre, Durham University, told the BBC that the causes Congressman Mercado mentioned, if proven true, created a "dangerous combination" that produced a "classic landslide scenario". [http://news.bbc.co.uk/2/hi/asia-pacific/4723770.stm "What caused Philippines landslide?"] , BBC, 17 February 2006]

However, local government officials and eyewitnesses say that the area was well forested and the governor's office said that deforestation logging activities were not the causal factor. [http://news.bbc.co.uk/2/hi/asia-pacific/4723770.stm "What caused Philippines landslide?"] , BBC, 17 February 2006]

Experts did agree that torrential rains lasting two weeks before the mudslide was the main cause for the disaster. Rainfall amounting to over 200cm (79 inches) in ten days loosened the soil so much that the resulting sludge and rocks thundered down the slopes of nearby Mount Can-abag, virtually disintegrating it. The La Niña weather phenomenon was blamed for the non-stop rains that occurred in the province, as well as in the Caraga region, which is due south of Leyte. San Francisco, Agusan del Sur mayor Carie Ladernora declared the state of calamity on her town by February 12, 2006.

The Philippine Institute of Volcanology and Seismology recorded a magnitude 2.6 earthquake in Southern Leyte just prior to the landslide although the effects of this are unclear. [http://news.bbc.co.uk/2/hi/asia-pacific/4723770.stm "What caused Philippines landslide?"] , BBC, 17 February 2006]

2008 workshop

After two years, the international geoscience community including experts from Japan, Canada, United States, Sri Lanka, New Zealand, Hong Kong, UK, Taiwan and the Phlippines, came together in Tacloban and St. Bernard to examine known information on the Guinsaugon disaster. In addition, the workshop was tasked with determining the next steps as Leyte and the Philippines move forward from the world's deadliest single-event landslide since 1998. The landslide is classified as a rock slide-debris avalanche using the Varnes (1978) [Varnes D. J.: Slope movement types and processes. In: Schuster R. L. & Krizek R. J. Ed., Landslides, analysis and control. Transportation Research Board Sp. Rep. No. 176, Nat. Acad. oi Sciences, pp. 11-33, 1978.] or Cruden and Varnes (1996) [Cruden D.M., VARNES D. J. (1996) - Landslide types and processes. In: Turner A.K.; Shuster R.L. (eds) Landslides: Investigation and Mitigation. Transp Res Board, Spec Rep 247, pp 36-75.] classification. Volume estimates in recent publications range between 14 Mm³ and 20 Mm³, converging on or about 15 Mm³. [Catane, S.G., Cabria, H.B., Zarco, M.A.H., Saturay, R.M., Mirasol-Robert, A.A. in press. The 17 February 2006 Guinsaugon rock slide-debris avalanche, Southern Leyte, Philippines: deposit characteristics and failure mechanism. Bulletin of Engineering Geology and the Environment. DOI 10.1007/s10064-008-0120-y, 16p.] [Catane,S.G., Cabria, H.B., Tomarong, C.P., Saturay, R.M., Zarco, M.A.H. and Pioquinto, W.C. 2007. Catastrophic rockslide-debris avalanche at St. Bernard, Southern Leyte, Philippines. Landslides, 4.] [Evans, S.G., Guthrie, R.H., Roberts, N.J., and Bishop, N.F. 2007. The disastrous 17 February 2006 rockslide-debris avalanche on Leyte Island, Philippines: a catastrophic landslide in tropical mountain terrain. Natural Hazards and Earth System Sciences, 7, 89 - 101.] [Orense, R.P. and Sapuay, S.E. 2006. Preliminary report on the 17 February 2006 Leyte Philippines landslide. Soils and Foundations, 45, 685-693.] [Makino, M., Mandanas, A.A. and Catane, S.G. 2007. Gravity basement of the Guinsaugon landslide along the Philippine Fault Zone. Earth Planets Space, 59, 1067 - 1071.] There is general accord among scientists that high precipitation a week prior to the failure contributed to the conditions at failure, but the 5 day delay between the rain and the landslide, and the fact that Southern Leyte regularly gets high overall levels of precipitation means that the precise nature of that contribution is unknown. Similarly, the role of minor ground shaking that occurred at about the same time is still uncertain. "Was the landslide caused by ground shaking or excessive rain? This is one of the things that is not yet resolved." said Dr. Mark Albert Zarco, a professor at the Department of Engineering Sciences, University of the Philippines, Diliman in a news story. Importantly, the geological and geomorphological history of the slope including, for example, the prominent strike-slip movement of about 2.5 cm per year, has ultimately lead to failures all along the scarp, including the one that buried Guinsaugon. Richard Guthrie, of University of Waterloo, Canada, stated: "We have had very large rains and we have had very large earthquakes in the past; The rocks have been stretched and strained. As time moves on, the rock begins to age and die and finally it collapses. The important thing is that we’re able to know the preconditioning of the slopes." [ [http://www.gmanews.tv/story/93460/Scientists-clueless-on-cause-of-Southern-Leyte-landslide www.gmanews.tv, Scientists clueless on cause of Southern Leyte landslide] ] Scientists are currently building a synthesis paper on the landslide and a set of recommendations regarding the next steps for the Philippines in relation to landslide hazards.

Mining operations

Religious leaders and civil authorities suspect that mining interests are behind the Southern Leyte tragedy.

The Supreme Court decision December last year reversing its earlier ruling concerning the legality of the Mining Act of 1995 has paved the way for U.S. and other foreign mining corporations to claim mining rights in the country, the report of the recently-concluded International Solidarity Mission (ISM) said. These corporations have particularly penetrated Samar and Leyte, islands in central Philippines which are rich in bauxite, nickel and copper.

The Mines and Geosciences Bureau (MGB) of the Department of Environment and Natural Resources (DENR) lists two mining companies which have an ongoing exploration in the region, particularly in Southern Leyte: The Buena Suerte Mining Corporation, which explores the areas near San Francisco, San Ricardo, Pintuyan and Liloan (6,611.59 has.) and Orophilippine Ventures, Inc., which explores Sogod, Liloan, St. Bernard and Libagon. Gold, silver, and other associated minerals can be mined in these areas.

May 2006 mudslide

Due to Typhoon Chanchu (Philippine name: Caloy), flash floods and mudslides isolated at least 11 barangays in Sogod, Southern Leyte. No casualties were reported. [ [http://news.inq7.net/top/index.php?index=1&story_id=75567 Storm triggers landslides; thousands stranded] , INQ7.net, 12 May 2006]

Footnotes

References

* [http://www.cbc.ca/world/story/2006/02/17/landslide-philippines060217.html 1500 Missing in Village Mudslide] - CBC Dean Bernardo 17 February 2006
* [http://news.bbc.co.uk/2/hi/asia-pacific/4728876.stm Philippine rescuers find bodies] - BBC News 19 February 2006
* [http://www.msnbc.msn.com/id/11400414/ Philippine rescue teams find more bodies] - MSNBC 19 February 2006
* [http://observer.guardian.co.uk/world/story/0,,1712975,00.html Hope fades for villagers in Philippine mudslide horror] - The Observer John Aglionby, 19 February 2006
* [http://www.dmrg.org/resources/news/2006/2006.02.17-Hundreds%20missing%20in%20Philippine%20landslide.pdf Hundreds Missing in Philippine Landslide] - DMRG 17 February 2006
* [http://news.inq7.net/nation/index.php?index=1&story_id=66625 Landslide triggers avalanche of international aid] - Philippine Daily Inquirer 19 February 2006
* [http://edition.cnn.com/2006/WORLD/asiapcf/02/17/philippines.landslide Mudslide buries Filipino village] - CNN 18 February 2006
* [http://news.bbc.co.uk/2/hi/asia-pacific/4722702.stm Mud wipes out Philippines village] - "BBC News" 17 February 2006
* [http://news.bbc.co.uk/2/hi/asia-pacific/4723770.stm What caused Philippines landslide?] - "BBC News" 17 February 2006
* [http://www.sunstar.com.ph/static/net/2006/02/12/caraga.region.under.state.of.calamity.html Caraga region under state of calamity] - SunStar News 12 February 2006
* [http://news.inq7.net/breaking/index.php?index=1&story_id=67088 North Korean leader offers condolences to landslide victims] - Philippine Daily Inquirer 22 February 2006
* [http://newsinfo.inquirer.net/inquirerheadlines/regions/view_article.php?article_id=135682 Living dangerously with landslides] - Philippine Daily Inquirer 10 May 2008

External links

* [http://maps.google.com/maps?f=q&hl=en&q=philippines&t=k&ll=10.271006,125.113678&spn=0.191882,0.334053&t=k St. Bernard, Leyte from Google Maps]
* [http://www.guinsaugon2008.com Official website of the 2008 International Conference-Website on the Guinsaugon Landslide]