GEOLOGY

EARTH SCIENCE

VOLCANOES

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A broad volcano with gently sloping sides is a ____
A
Shield
B
Cinder Cone
C
Fire Fountain
D
Composite
Explanation: 

Detailed explanation-1: -Where a volcano produces low viscosity, runny lava, it spreads far from the source and forms a volcano with gentle slopes: a shield volcano. Most shield volcanoes are formed from fluid, basaltic lava flows. Mauna Kea and Mauna Loa are shield volcanoes.

Detailed explanation-2: -Although shield volcanoes are the largest volcanoes on Earth, they do not form soaring mountains with conical peaks like composite volcanoes. Instead, they are broad volcanoes with gentle slopes and are shaped somewhat like a warrior’s shield lying flat on the Earth.

Detailed explanation-3: -Shield volcanoes, the third type of volcano, are built almost entirely of fluid lava flows. Flow after flow pours out in all directions from a central summit vent, or group of vents, building a broad, gently sloping cone of flat, domical shape, with a profile much like that of a warrior’s shield.

Detailed explanation-4: -The gentle slopes are the result of the low lava viscosity, allowing lavas to flow fast and far. The lava flows (pahoehoe and aa) commonly initiate their path from flank vents and fissures rather than from the summit. These flank vents are the result of the widening and / or subsidence of the volcano.

Detailed explanation-5: -A shield volcano takes its name from its shape, which looks like a warrior’s shield seen from the side. It’s much wider than it is high. Shield volcanoes are built up of a great many flows of runny lava, each of which is relatively thin, only a few meters (yards) thick.

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