Mass movement is one of the most catastrophic events which covers a substantial amount of land areas. The phenomenon happened when bulk movements of soil and rock debris down slopes due to gravity or gradual sinking of earth’s surface. Briefly, the term mass movement refers to sinking of a confined area in the earth’s surface, this means that mass of soil and rock moves from one place to another. This means that any sediments will be moved by the gravity on a downward slope of a surface (Britannica). There are various types of mass movements categorized by geographical caucus. (BBC)
Rockfall: Bits of rock fall due to freeze thaw
Mudflow: Saturated soil with high concentration of water flows down slope
Landslide: Rock debris falling down a downward slope
Rotational Slip: saturated soil slumps flows down the slope
There are 2 known cases recently that have been reported ranted by mass media, those are the 2018 Montecito Mudflow and recent rockfall trends in the Mountains of Alps. Both events are 2 different types of mass movements. The 2018 Montecito Mudflow killed at least 17 people and trapped almost 300 residents in the district. It is reported that the Mudflow was initiated from heavy rains that happened early Tuesday that caused rivers of mud mixed with debris to flow down the downward slope of Santa Barbara hill. The disaster destroyed almost 100 homes and damaged 300 homes, the mayor of California issued a mandatory evacuation procedure for 7,000 people and believe that the district of Montecito is vulnerable due to the fact that it is situated near a steep hill subsequently burned acres of land that was showered by the rain can move down from the hill into the city at a fast rate (CNN). As reported, wildfires in December change the soil condition causing it to be more prone and slippery to erosion. Geographically Montecito is surrounded by a meter wide mountain channel which could be damp when a storm batters those locations. Hence, if the channels are filled with fluids it will move downhill growing both in momentum (speed towards the district) and volume (amount of mudflow). It will then wipe out infrastructure that stands against their pathway. (NY Times)
In a different case, recently there has been a trend of rockfall in the mountain of Alps situated specifically in the district of Bondo village where it got struck by a 4 million cubic meter of rock and mud. Marcilia Philips, permafrost analyst, explained that there has been a distinct warming in the rock walls of the alps. This explains why there are huge chunks that were fractured and caused the disaster respectively (BBC). Climate change has a direct effect on the disaster, it deteriorates the structure of glaciers. Those glaciers are an integral part of the mountain where it supports the rock, protects from precipitation, and prevents erosion. If this continues due to the greenhouse gases emission which causes the increase of global temperature, by 2050 the glaciers will be fully melted and villagers down in the valley will be expecting rockfalls. In recent reports, the catastrophic event killed 8 hikers already. (Guardian.co.uk)
Photo 1: Endangered site in the Alps mountain
Personally, I would say that Montecito cases are far more dangerous besides having more casualties recently in the near future if such a trend is maintained; more casualties and damage to the infrastructure could be resulted. Although, Bondo village (28,28 km2) is bigger than the Montecito district (23.99 km2). However, it is far more populated which can cause more casualties and more buildings being damaged. Montecito has more residences than Bondo village. This factor makes the catastrophic event more severe than what happened in the Alps.
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