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.
What type of magma explodes?
Explosive Eruptions
Felsic magmas
erupt explosively because of hot, gas-rich magma churning within its chamber. The pressure becomes so great that the magma eventually breaks the seal and explodes, just like when a cork is released from a bottle of champagne.
Which type of magma is most explosive form of magma?
Explosive eruptions are favored by high gas content and high viscosity (
andesitic to rhyolitic magmas
). Explosive bursting of bubbles will fragment the magma into clots of liquid that will cool as they fall through the air.
What type of lava is most explosive?
Viscous lava will trap pockets of gas within the rock, and not let them pop as bubbles on the surface. But most importantly,
highly viscous lava
is associated with explosive eruptions and dangerous pyroclastic flows. An example of a low viscosity (fast flowing) lava is basaltic lava.
What is explosive magma?
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! Lava flows are much more thick and sticky so do not flow downhill as easily.
What are 3 types of magma?
There are three basic types of magma:
basaltic, andesitic, and rhyolitic
, each of which has a different mineral composition. All types of magma have a significant percentage of silicon dioxide. Basaltic magma is high in iron, magnesium, and calcium but low in potassium and sodium.
What is the difference between magma and lava?
Scientists use the term
magma
for molten rock that is underground and lava for molten rock that breaks through the Earth’s surface.
Which magma has the highest viscosity?
The magma that has the highest viscosity is
rhyolitic magma
.
Which components of magma is the highest and the lowest in value?
Felsic magma
has the highest silica content of all magma types, between 65-70%. As a result, felsic magma also has the highest gas content and viscosity, and lowest mean temperatures, between 650
o
and 800
o
Celsius (1202
o
and 1472
o
Fahrenheit).
How deep is magma in the earth?
A layer of molten rock trapped since Earth’s formation may exist where the solid mantle meets the core, a new study says. A layer of searing hot liquid magma trapped since Earth’s formation may lie
1,800 miles (2,900 kilometers) beneath our feet
, new research suggests.
What are the 3 types of volcano?
Individual volcanoes vary in the volcanic materials they produce, and this affects the size, shape, and structure of the volcano. There are three types of volcanoes:
cinder cones (also called spatter cones), composite volcanoes (also called stratovolcanoes), and shield volcanoes
.
What is the most destructive volcano?
| Eruption Year Casualties | Mount St. Helens , Washington 1980 57 3 | Kilauea, Hawaii 1924 1 1 | Lassen Peak, California 1915 0 4 | Mount Vesuvius, Italy 79 A.D. 3,360 2 |
|---|
Which volcano is the 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 material.
Is magma hotter than lava?
Magma is
hotter than lava
, depending on how recently the lava reached the surface and if the magma and lava are from the same magma chamber below the…
Which types of magma contain the least amount of Sio?
| SiO2 CONTENT MAGMA TYPE VOLCANIC ROCK | ~50% Mafic Basalt | ~60% Intermediate Andesite | ~65% Felsic (low Si) Dacite | ~70% Felsic (high Si) Rhyolite |
|---|
What is silent eruption?
Technically speaking, “quiet” eruptions are known as
effusive eruptions
. These relatively tame eruptions are characterized by an outpouring of thin, liquid-like lava, as seen with many Hawaiian volcanoes.
