What makes some volcanic eruptions more explosive than others?
It’s the more viscous lava, the stiffened molten rock, that creates a more explosive eruption as opposed to an effusive one. “These eruptions have the potential to influence global climate,” the authors wrote in their study.
Why are some volcanic eruptions more explosive than others quizlet?
Because basaltic lavas are less viscous, they produce relatively gentle eruptions, while volcanoes that erupt felsic lavas ( rhyolite and andesite) tend to be more explosive. Volcanoes and earthquakes both result from the movement of tectonic plates.
Which volcanoes are more likely to explode?
Composite volcanoes are some of the most dangerous volcanoes on the planet. They tend to occur along oceanic-to-oceanic or oceanic-to-continental boundaries because of subduction zones. They tend to be made of felsic to intermediate rock and the viscosity of the lava means that eruptions tend to be explosive.
What causes explosive eruptions?
Explosive eruptions occur where cooler, more viscous magmas (such as andesite) reach the surface. Dissolved gases cannot escape as easily, so pressure may build up until gas explosions blast rock and lava fragments into the air!
Why are some volcanic eruptions explosive while others are quiescent?
Explain why some volcanic eruptions are explosive and others are quiescent. High- silica, low- temperature lavas are the most viscous and allow the greatest amount of pressure to build up before they ” let go” in an eruption. In contrast, lavas that are hot and low in silica are the most fluid.
Why do some volcanic eruptions consist mostly of effusive lava flows whereas others are explosive and do not produce lava flows?
Effusive eruptions only. Why do some volcanic eruptions consist mostly of lava flows, while others are explosive and do not produce flows? Because of its viscosity. If it has high viscosity (felsic) then gas and volatiles cannot escape easily and pressure is built up causing an explosive eruption.
What type of volcano is the most explosive?
Stratovolcanoes are considered the most violent. Mount St. Helens, in Washington state, is a stratovolcano that erupted on May 18, 1980.
What type of eruption is the most explosive?
The largest and most violent of all the types of volcanic eruptions are Plinian eruptions. They are caused by the fragmentation of gassy magma, and are usually associated with very viscous magmas (dacite and rhyolite).
What are the effects of an explosive volcanic eruption?
Volcanic ash can make breathing difficult and can cause buildings and structures to collapse (especially when the ash is wet), damage agricultural crops, and contaminate grass used for livestock feed. The downwind ash plume from such eruptions also poses a hazard to aircraft.
What happens when volcanoes explode?
Explosive volcanic eruptions can be dangerous and deadly. They can blast out clouds of hot tephra from the side or top of a volcano. These fiery clouds race down mountainsides destroying almost everything in their path. Ash erupted into the sky falls back to Earth like powdery snow.
Why do some volcanic eruptions consist mostly of lava flows while others are explosive and do not produce flows?
Why do some volcanic eruptions consist mostly of lava flows, while others are explosive and do not produce flows? Because of its viscosity. If it has high viscosity (felsic) then gas and volatiles cannot escape easily and pressure is built up causing an explosive eruption.
What makes an eruption more explosive?
A volcano’s explosiveness depends on the composition of the magma (molten rock) and how readily gas can escape from it. As magma rises and pressure is released, gas bubbles (mainly of water vapor and carbon dioxide) form and expand rapidly, causing explosions.
What is the difference between explosive and effusive volcanic eruptions?
Effusive eruptions consist of a gentle and steady flow of lava on the surface, while explosive eruptions are violent phenomena that can eject hot materials up to several kilometres into the atmosphere. The transition between these eruptions represents one of the most dangerous natural hazards.
How does the type of magma affect a volcano’s Explosivity?
The type of magma, and ultimately the classification of volcano that is created, is a huge physical factor in determining a volcano`s explosivity. Magma comes in many forms and each chamber is unique. Therefore, a wide spectrum of lava types can occur.
Why do volcanoes erupt?
The magma isn’t very liquid-y, so it is able to trap gases in the depths, allowing the pressure inside the volcano to build. When these volcanoes erupt, they explode with a bang. The more explosive volcanoes are kind of like soda bottles with lots of trapped gas.
How is the explosiveness of a volcano measured?
The explosiveness can be measured by the Volcanic Explosivity Index (VEI); the higher the VEI, the greater the potential hazard. The type of magma, and ultimately the classification of volcano that is created, is a huge physical factor in determining a volcano`s explosivity.