Volcanic Eruptions
Describe pyroclastic material and lava flows
What is pyroclastic material?
Volcanic Ash and Dust
When pyroclastic particles that are less than 2cm in diameter it's I called volcanic ash when it is 0.25mm in diameter it is called volcanic dust this small particles surround the volcano once it hits the ground and some that are smaller go to the upper atmosphere
Lapilli
Large pyroclastic material that are less than 64mm in diameter are called Lapilli. Lapillis fall near the vent of the volcano.
Volcanic bombs and Voclanic Blocks
Volcanic bombs are large red clots of lava that come out when the volcanoes erupt. They cool when they are in the air they form a spindle shape. Volcanic blocks are more dangers there the largest pyroclastic material they form as solid rock and it blasts from the vent of the volcaneo, some are the size of small house.
What are the Types of Mafic Magma?
Types of lava
Pahoehoe Lava
Its less viscous, it forms wrinkly volcanic rock when it cools.
Aa Lava
Is more viscous than pahoehoe lava and forms sharp volcanic rock when it cools
Blocky Lava
Is the most viscous type of mafic magma and forms chunky volcanic rock when it cools
Lava Flows
Types of volcaneos
Cinder cones
Mount Etna. A type of volcaneos that has a very steep slope is a cinder cone, the slope angles of the cinder cones can be close to 40’and the slopes are rarely mare than few hundred meters high. Cinder cones form from explosive eruptions and are made of pyroclastic.
Shield volcaneos
Mauna Loa.A shield volcano overs a wide area and generally forms from quiet eruptions,layers of hot mafic lava flow out around the vent, harden slowly built up form the cone
Composite volcanoes
Mount Fiji.Composite volcanoes are made of alternating layers of hardened lava flow and pyroclastic material. During a quiet eruption lava flows cover the sides of the cone. Then when a violent eruptions occurs large amounts of pyroclastic material are des around the vent. Composite volcanoes are also known as Saratovolcanoes.