According to the business anti-corruption portal , The Philippines has vast natural resources and in order to protect resources, such as natural forests and rare animal species, the Philippines has introduced an anti-logging campaign. The campaign is directed mainly toward local small and medium-sized logging companies, whereas the large companies go untouched. Large logging companies feel that they can act with impunity because they have so much political influence through donations, bribes or personal relationships. Therefore, these companies can freely log more trees than their licence allows.
Large logging companies are cutting trees beyond the area granted by their permits, i.e., they are engaged in illegal logging. They enjoy such impunity because of the personal connections between owners and high level government officials. An example of this close relationship is the former Environment Secretary, Michael Defensor, who is a friend of the Chua family who own Toplite Lumber Corporation, one of the largest lumber companies in the Philippines.
I must remind users of this Forum to stick with the subject of the thread to maintain consistency. If you want to exchange viewpoints about landslides, then stick with the subject thread. Otherwise, create another thread if you solicit viewpoints about something else... Thank you...
'Nuff said...
Webmaster
"Oh, the Good Life, full of fun, seems to be the ideal."
Causes of landslides: 1. When the earth is fully saturated, it is prone to landslides. The reason that vegetations are needed on forest to withhold surface runoff. Trees and other vegetations will absorb the surface water during rain. 2. Plasticity of the soil. Clay has more ability to withstand the slope than the granular soil but then this resistance will be greatly reduced when it is saturated. 3. When there is/are geologic faults that may cause the water to sip-in resulting a massive landslides. 4. Soil can withstand to a certain slope. Hard and soft rocks can withstand a steeper slope than a common earth. Plans of a road project indicates the design slopes. 5. Underground water when confined in a tunnel like hard strata will come out in lower ground as spring. Underground water confined in a soft strata will spread underneath creating a plane of slide. This phenomenon as you have observed will create a longuitudinal crack especially on roads. There were cases of roads that gradually collapsed starting from longuitudinal cracks. These are called road slips. 6. Manmade. All projects that may affect the ecology of the environment must secure an Environmental Clearance Certificate (ECC) from DENR. In road projects ,all trees affected by the widening must be replanted similar to logging operations. But because of some political influence, these requirements were not being followed that leads to disaster, hence manmade. A geologist or mining engineer can provide us a full technical explanations :
Point: The causes are the lack of regulation, abuse of power, improper zoning, negligence to the environment and corruption. Leyte landslide such as Ormoc and Guinsawgon are the results.
good point here.trees are major raw materials in our poor country, including para sugnod. cutting of trees are being regulated not only by local ordinances but by national laws. the problem really lies on the residents where illeal cutting happened. without the vigilance of these residents, landslides is always a probability.
Causes of landslides: 1. When the earth is fully saturated, it is prone to landslides. The reason that vegetations are needed on forest to withhold surface runoff. Trees and other vegetations will absorb the surface water during rain.
Certain soil properties are prone to extreme saturation resulting in liquefaction. Depending on the steepness and length of the slope and soil properties, landslides or "slumps" could occur. Trees and other types of vegetative ground cover can indeed protect the top soil from eroding as they tend to dissipate the energy of surface water runoff while decelerating runoff velocity. However, because tree roots hold water, they are also attributable to deeper infiltration of surface water during extensive precipitation. More so during high winds when tree trunks sway serving as dynamic wedges on the surface thus causing a widening gap between their roots for surface water to readily enter into the ground. When water becomes heavy on the top side, it's volume can spread laterally and vertically. When soil resistance at the toe of slope becomes overwhelmed with the weight of the water, there's only one way for the ground to go - and that is downhill - thus a landslide occurs.
2. Plasticity of the soil. Clay has more ability to withstand the slope than the granular soil but then this resistance will be greatly reduced when it is saturated.
Plasticity is a type of soil property that is also influenced by porosity and composition. When porosity is miniscule, hydraulic conductivity literaly is low. Clayey soils are well packed, dense and heavy. However, when the pores in-between the grains of clay soil becomes well saturated, plasticity is lessened thus negatively affecting the tensile strength of the soil. Clay soils are normally prevalent on flat lands, swales, rolling hills or valleys. If they are on steep mountain ranges, they can be also give way to landslides that are triggered by seismic forces.
3. When there is/are geologic faults that may cause the water to sip-in resulting a massive landslides.
When surface water infiltrates the top horizon of soil at geologic faults, indeed landslide or slumps occur at areas where critically steep slopes exist. Faults are pretty much the earth's cracks that are caused by diastrophism, subduction of tectonic plates, volcanic eruptions, or sometimes separation of two or more areas of distinct soil properties that disbond during seismic events.
4. Soil can withstand to a certain slope. Hard and soft rocks can withstand a steeper slope than a common earth. Plans of a road project indicates the design slopes.
From a civil engineering standpoint, road design entails a lot of consideration for prevailing conditions which might influence the usability and longevity of the road. In certain cases, compaction of existing virgin soil is necessary before the application of subgrade materials such as gravel, crusher run, rocks, etc. And the durability of concrete (if used) must be matted with properly sized rebars to minimize if not eliminate cracking that results from constant vibration (vehicular impositions), material expansion and contraction, etc. Properly designed roads seem to hold better and much stronger even when subjected to soil slumps or underminings.
5. Underground water when confined in a tunnel like hard strata will come out in lower ground as spring. Underground water confined in a soft strata will spread underneath creating a plane of slide. This phenomenon as you have observed will create a longuitudinal crack especially on roads. There were cases of roads that gradually collapsed starting from longuitudinal cracks. These are called road slips.
6. Manmade. All projects that may affect the ecology of the environment must secure an Environmental Clearance Certificate (ECC) from DENR. In road projects ,all trees affected by the widening must be replanted similar to logging operations. But because of some political influence, these requirements were not being followed that leads to disaster, hence manmade.
If I might add, roads that are improperly routed through critical areas where the natural foundation of toes of slopes is dynamically compromised, can cause landslides or slumps.
Lastly, it is somewhat a misnomer to think that landslides are caused by over-logging. Not necessarily so. Over-logging may cause an eventual increase in velocity and/or volume of surface water runoff as well as erosion and silt deposition at downgradient areas. However, major landslides are natural phenomena caused by seismic and weather-borne forces upon pre-existing topography and geologic structure of soils. Meanwhile, minor landslides are manmade ones that are almost proportionate to the surface disturbances (i.e. ill-designed roads and drainage systems, improper surface grading or compaction, improper retention or foundation design, etc.) that had caused them in the first place.
"Oh, the Good Life, full of fun, seems to be the ideal."
Page: 1
Author
Leyte Landslide, What caused it? 
Female
Logged
Male
And your point about landlside is????
Certain soil properties are prone to extreme saturation resulting in liquefaction. Depending on the steepness and length of the slope and soil properties, landslides or "slumps" could occur. Trees and other types of vegetative ground cover can indeed protect the top soil from eroding as they tend to dissipate the energy of surface water runoff while decelerating runoff velocity. However, because tree roots hold water, they are also attributable to deeper infiltration of surface water during extensive precipitation. More so during high winds when tree trunks sway serving as dynamic wedges on the surface thus causing a widening gap between their roots for surface water to readily enter into the ground. When water becomes heavy on the top side, it's volume can spread laterally and vertically. When soil resistance at the toe of slope becomes overwhelmed with the weight of the water, there's only one way for the ground to go - and that is downhill - thus a landslide occurs.
