MONTERREY, MEXICO: A GOOD EXAMPLE ON A BAD PLANNING
July 2005- after some intense rains caused by the hurricane Emily in the city of Monterrey, N. L., Mexico, enormous cracks appeared in the slums located on an area called "the Lajas". The residents had to leave their homes because of a great mass of rocks that moved downward, threatening on destroying and covering their residences.
Neighbors, very well-off people from the city, blamed to a multifamily edifice that was constructed at a few meters from the colony where they lived quietly. They requested to the authorities the demolition of the building, and because they thought that the building was the straight responsible of the instability of the zone. They were and still are mistaken -or badly advised- then the geologic studies of the Sierra Madre Oriental -where they constructed their mansions- reveal that in that area they must never have constructed a single residence. I support the last expression on the following facts:
1. Displacement of complete masses of rock and earth.
2. Formation of cracks and slopes in the land.
3. Loss of verticality of poles, trees and structures perpendicular with respect to the floor.
4. Tendency of the ground, in this case, tendency of strata, highly fragile.
5. Type of Ground, for this case, dolomite and limestone sedimentary soil.
6. Hardness of the rocks, for this case, hardness 2, that is, only a degree over gypsum.
7. Potential energy accumulated on rocks (about 3.63 x 107 J).
8. Pattern of folding. In the Cerro de las Mitras, the folds have been denuded by natural erosion.
9. Direction of the slope. In the Cerro de las Mitras, specifically in the site where there are human settles, including a Commercial Center ("Soriana") and the Hidden Lake, the slope of alluvia and water follows exactly a threatening direction toward these establishments.
10. Absence of magma Rocks. There are not volcanic rocks in Cerro de las Mitras.
My scientific conclusion is that the ground movement obeyed to an exacerbation of the natural movement of crawling due to the overload of a heavy filling and the addition of construction materials on a mass of rock already debilitated by natural processes. I should add that also the depredation of the green areas, which consisted of an ecosystem of sub-mountain scrub, contributed to the weakening of the stony mass.
ATTENTION: Now, the authorities have hurried in the retirement of the filling material from the affected area, causing a collapse of another mass of rock in the edge located upwards the disturbed bank. From now on, the danger for the settlements located down the mountain is greater than before the removing of the filling; however, the worse thing is than if they take apart the building that caused the whole problem, then the two masses of rocks and gravel will come down… crushing the inhabited homes... Remember Hudson Parkway?