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A ‘Lahar’ is a geographical hazard specifically involving:
A lahar is a specific geographical hazard where water and volcanic fragments combine to form a high-speed slurry. These mudflows are often triggered by the sudden melting of snow and ice during an eruption or by intense rainfall on unstable ash deposits. Because they follow existing drainage patternRead more
A lahar is a specific geographical hazard where water and volcanic fragments combine to form a high-speed slurry. These mudflows are often triggered by the sudden melting of snow and ice during an eruption or by intense rainfall on unstable ash deposits. Because they follow existing drainage patterns like river valleys, they can impact communities dozens of miles away from the eruptive site. Lahars are incredibly destructive due to their high density and velocity; they can carry boulders and destroy bridges. The 1985 eruption of Nevado del Ruiz in Colombia remains a tragic example of the lethal power of lahars.
See less‘Fissure eruptions’ are most likely to occur in which geographical setting?
Fissure eruptions occur when magma reaches the surface through long linear cracks rather than a single pipe. This is the dominant form of volcanism at mid-oceanic ridges, where tectonic plates diverge. Geographically, these eruptions are responsible for the seafloor spreading process that constantlyRead more
Fissure eruptions occur when magma reaches the surface through long linear cracks rather than a single pipe. This is the dominant form of volcanism at mid-oceanic ridges, where tectonic plates diverge. Geographically, these eruptions are responsible for the seafloor spreading process that constantly renews the ocean floor. On land, fissure eruptions create “flood basalts” that form extensive volcanic plateaus. Because the basaltic lava is highly fluid, it floods the landscape in thin, horizontal layers. This type of volcanic activity is less explosive but geographically significant for building the Earth’s most extensive igneous rock provinces.
See lessWhich gas released during eruptions can lead to ‘Global Cooling’ by reflecting solar radiation?
While volcanoes release Carbon Dioxide, it is Sulfur Dioxide that significantly impacts global climate by causing cooling. When a powerful eruption sends SO2 into the stratosphere, it converts into sulfuric acid aerosols. These tiny particles stay suspended for years, reflecting sunlight away from ERead more
While volcanoes release Carbon Dioxide, it is Sulfur Dioxide that significantly impacts global climate by causing cooling. When a powerful eruption sends SO2 into the stratosphere, it converts into sulfuric acid aerosols. These tiny particles stay suspended for years, reflecting sunlight away from Earth—a process known as “volcanic forcing.” The 1991 eruption of Mount Pinatubo, for example, cooled the Earth by about 0.5°C for several years. This geographical phenomenon highlights the profound link between volcanic emissions and short-term climate variability, occasionally leading to “years without a summer” following massive historical eruptions.
See less‘Geysers’ and ‘Hot Springs’ are most commonly found in:
Geographically, geysers and hot springs serve as external indicators of subterranean volcanic heat. They are primarily found in volcanic "hotspots" or active plate boundaries like Yellowstone, Iceland and New Zealand. For these to form, groundwater must seep down near hot igneous rocks. In a hot sprRead more
Geographically, geysers and hot springs serve as external indicators of subterranean volcanic heat. They are primarily found in volcanic “hotspots” or active plate boundaries like Yellowstone, Iceland and New Zealand. For these to form, groundwater must seep down near hot igneous rocks. In a hot spring, the water rises and circulates freely. In a geyser, a constricted plumbing system prevents free circulation, allowing water to become superheated. The resulting steam pressure eventually forces a violent eruption of water. These features are significant for tourism and are often exploited for sustainable geothermal energy production.
See lessThe ‘Black Soil’ (Regur) of India is highly fertile because it is derived from the weathering of: (A) Granite rocks (B) Basaltic lava rocks (C) Sandstone (D) Metamorphic rocks
India's "Regur" or Black Cotton Soil is a direct geographical legacy of ancient volcanic activity. It formed from the mechanical and chemical weathering of basaltic lava deposited during the Deccan Trap eruptions at the end of the Cretaceous period. This soil is rich in lime, iron and magnesium butRead more
India’s “Regur” or Black Cotton Soil is a direct geographical legacy of ancient volcanic activity. It formed from the mechanical and chemical weathering of basaltic lava deposited during the Deccan Trap eruptions at the end of the Cretaceous period. This soil is rich in lime, iron and magnesium but poor in phosphorus and nitrogen. Its most unique geographical property is its “self-ploughing” nature—it develops deep cracks during the dry season, allowing for aeration and becomes sticky when wet. This fertile soil is the backbone of agriculture in the Deccan region, particularly for moisture-dependent crops like cotton and sugarcane.
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