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Multiple Choice Questions (MCQs)
Which of the following results in destruction of vegetation?
(a) Earthquake
(b) Tsunami
(c) Volcanic eruption
(d) All of these
Answers
Answer:
d) All of these
Explanation:
a) Earthquake -Geo-hazards induced by earthquakes have caused ecosystem degradation and vegetation destruction. Little, however, is known about the consequences of geo-hazards due to a lack of research data. We have undertaken a study in the Wenchuan earthquake-affected area of China in order to identify and characterize vegetation destruction and its consequent environmental impact. The Wenchuan earthquake on 12th May, 2008 induced numerous geo-hazards (including rock avalanches, landslides, landslide-dammed lakes and debris flows) that caused vegetation destruction up to 1249.5 km2, of which shrub comprised the largest proportional area with 338.559 km2. The vegetation coverage decreased by 4.76% in 9 severely damaged cities and counties and by 12.37% in the Subao river, Beichuan county. Rock avalanches and landslides were the most common destructive types, resulting in 98.73% of all types of geo-hazards, whereas debris flows and landslide-dammed lakes accounted for 1.27%. Vegetation destruction was distributed along both sides of rivers causing erosion, formation of debris flows and landslides. Hydrologic progress was changed and hydrological adjusting function diminished due to vegetation deterioration resulting in bare rock (infiltration reduced, runoff increased and flow concentration expedited) and deposit region (infiltration increased and runoff reduced) in catchment. Soil erosion was intensified causing increased sediment transportation of rivers, decreased storage capacities of reservoirs downstream, a significantly increased area that has suffered severe erosion and aggravated magnitude and damage capability of debris flows and landslides
Tsunami- In addition to strong shaking during earthquakes and the potential for tsunamis along the coast, there are location-specific hazards that can cause additional damage: surface rupture, liquifaction, and landslides.
Volcanic eruption - Volcanic activity both destroys or modifies existing vegetation and creates new geological substrates upon which vegetation can re-establish. ... We divide the volcanic activities into six categories: lava formation, pyroclastic flows, debris avalanches, mudflows, tephra and ash depositions, and blowdowns.