Why are shield volcanoes less explosive than?
The magma that creates shield volcanoes is less viscous so it flows much more easily. For this reason the eruptions of shield volcanoes are non-explosive. In addition the less viscous lava spreads out more which makes shield volcanoes much larger and flatter than stratovolcanoes.
Do shield volcanoes erupt slowly?
Active shield volcanoes experience near-continuous eruptive activity over extremely long periods of time, resulting in the gradual build-up of edifices that can reach extremely large dimensions. With the exclusion of flood basalts, mature shields are the largest volcanic features on Earth.
Who do shield volcanoes have weak eruptions?
Eruptions at shield volcanoes are only explosive if water somehow gets into the vent otherwise they are characterized by low-explosivity fountaining that forms cinder cones and spatter cones at the vent however 90% of the volcano is lava rather than pyroclastic material.
Is shield volcano least explosive?
Shield volcanoes tend to be the least explosive volcanoes. Most of the material they produce is lava, rather than the more explosive pyroclastic…
Are shield volcanoes explosive or effusive?
effusive Shield Volcano: A shield volcano has low levels of dissolved gas and silica in its magma. Its eruptions are effusive, and the fluid lava moves quickly away from the vent, forming a gently sloping volcano.
What type of eruption does a shield volcano have?
Most shield volcano eruptions are nonexplosive (effusive), usually 0-1 on the Volcanic Explosivity Index (VEI), typically in the Hawaiian eruptive style. These eruptions produce fluid lava flows and may produce fire-fountains. High rates of eruptions help produce lava flows that travel fast and can cover large areas.
What are three facts about shield volcanoes?
Fun Facts About Shield Volcanoes
- There is a short duration(s) between two consecutive eruptions. …
- The sides of these volcanoes are gentle rather than being sharp, as the lava travels a long distance before solidifying. …
- There is no layering as the lava itself solidifies for the formation of these volcanoes.
Why do shield volcanoes have wide bases?
Shield Volcanoes, Cinder-Cone Volcanoes and Composite Volcanoes. Why do shield volcanoes have wide bases? The lava is so runny, it spreads over a wide area.
Which volcanoes have the least explosive eruptions?
The least explosive type of volcano is called a basalt plateau. These volcanoes produce a very fluid basaltic magma with horizontal flows. The form of these volcanoes is flat to gently sloping and they can occupy an area from 100,000 to 1,000,000 square kilometers.
What type of eruptions do shield volcanoes have?
Most shield volcano eruptions are nonexplosive (effusive), usually 0-1 on the Volcanic Explosivity Index (VEI), typically in the Hawaiian eruptive style. These eruptions produce fluid lava flows and may produce fire-fountains. High rates of eruptions help produce lava flows that travel fast and can cover large areas.
Why are shield volcanoes effusive?
Effusive eruptions occur when hot, (1200oC) runny basalt magmas reach the surface. Dissolved gases escape easily as the magma erupts, forming lava that flows downhill quite easily. Effusive eruptions build up gently-sloping Shield Volcanoes like Hawaii.
Are shield volcanoes effusive or explosive?
effusive Shield Volcano: A shield volcano has low levels of dissolved gas and silica in its magma. Its eruptions are effusive, and the fluid lava moves quickly away from the vent, forming a gently sloping volcano.
What kind of eruptions do shield volcanoes have?
Most shield volcano eruptions are nonexplosive (effusive), usually 0-1 on the Volcanic Explosivity Index (VEI), typically in the Hawaiian eruptive style. These eruptions produce fluid lava flows and may produce fire-fountains. High rates of eruptions help produce lava flows that travel fast and can cover large areas.
What is unique about shield volcanoes?
Interesting Shield Volcano Facts: The way that a volcano gets its shape is determined by the lava. Shield volcanoes have low viscosity lava, described as being basaltic. Shield volcanoes' low viscosity lava means that the lava is more liquid and flows more quickly than thick lava.
Why do shield volcanoes have very gentle slopes?
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.
What type of eruption does shield volcanoes have?
Most shield volcano eruptions are nonexplosive (effusive), usually 0-1 on the Volcanic Explosivity Index (VEI), typically in the Hawaiian eruptive style. These eruptions produce fluid lava flows and may produce fire-fountains. High rates of eruptions help produce lava flows that travel fast and can cover large areas.
What is the weakest volcano?
The weakest are Hawaiian and submarine, then Strombolian, followed by Vulcanian and Surtseyan. The stronger eruptive types are Pelean eruptions, followed by Plinian eruptions; the strongest eruptions are called Ultra-Plinian.
Are shield volcanoes violent?
Shield volcanoes are a type of volcano that tend to erupt basalt lava. Because basalt has a low viscosity (more watery), it can flow on the surface better. So when these types of volcanoes erupt, lava flows outwards large distances. For a shield volcano, violent explosions are possible.
What are the characteristics of shield volcanoes?
Shield volcanoes are characterized by broad, gently sloping flanks and a dome shape that resembles an ancient warrior's shield. These volcanoes are built almost entirely of layers of solidified basaltic lava flows.
Why are shield volcanoes not steep?
Shield Volcanoes are composed of basaltic magma (high in temperature, very low on silica and gas content.) The lava erupted from the shield volcanoes are runny and non-acidic. As the erupted lava is runny, they flow long distances before they solidify, this results in the gentle sides of shield volcanoes.
What type of eruption is the weakest?
The weakest are Hawaiian and submarine, then Strombolian, followed by Vulcanian and Surtseyan. The stronger eruptive types are Pelean eruptions, followed by Plinian eruptions; the strongest eruptions are called Ultra-Plinian.
What type of volcano has the least violent eruption?
Strombolian and Hawaiian eruptions These are the least violent types of explosive eruptions.
Why are composite volcanoes more explosive than shield volcanoes?
Lavas and pyroclastics are usually andesitic to rhyolitic in composition. Due to the higher viscosity of magmas erupted from these volcanoes, they are usually more explosive than shield volcanoes.
Why do shield volcanoes have gentle slopes?
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.
How does a shield volcano differ from a composite volcano?
What is the main difference between a shield volcano and a composite volcano? The main difference between the two is that a shield volcano is composed of basaltic lava while a composite volcano is composed of andesitic magma.
What type of eruption is a shield volcano?
Eruption Types and Classification Most shield volcano eruptions are nonexplosive (effusive), usually 0-1 on the Volcanic Explosivity Index (VEI), typically in the Hawaiian eruptive style. These eruptions produce fluid lava flows and may produce fire-fountains.