12
Mar
The general cycle of activity of andesitic and dacitic volcanoes may be described by quiescence phreatic explosive activity with the formation of a new crater and repeated dome building and destruction accompanied by explosions. The Volcanic Explosivity Index VEI is a relative measure of the explosiveness of volcanic eruptionsIt was devised by Chris Newhall of the United States Geological Survey and Stephen Self at the University of Hawaii in 1982.
There are different kinds of volcanoes according to activity around the world that are classified as dormant volcanoes active volcanoes and extinct volcanoes.
Explain how scientists classify volcanoes according to volcanic activity. There is no easy answer to this question as scientists classify volcanoes in several different ways including size shape explosivity lava type and tectonic occurrence. Volcanoes are classified as active dormant or extinct. Active volcanoes have a recent history of eruptions.
They are likely to erupt again. Dormant volcanoes have not erupted for a very long time but may erupt at a future time. Extinct volcanoes are not expected to erupt in the future.
Volcanoes come in many different shapes and sizes but are most commonly cone-shaped hills or mountains. They are found throughout the world forming ridges deep below the sea surface and mountains that are thousands of meters high. About 1900 volcanoes on Earth are considered active meaning they show some level of occasional activity and are likely to erupt again.
Volcanoes are the geologists window into the Earths interior. If you recall from the previous section plate tectonics directly influences the location and types of volcanoes we find across the globe. There are different kinds of volcanoes according to activity around the world that are classified as dormant volcanoes active volcanoes and extinct volcanoes.
These volcanoes are further classified as per their shape composite volcanoes cinder cones lava domes and shield volcanoes. An active volcano is a volcano that has a record of eruption within the last 600 years or has erupted 10000 years ago based on analyses of its materials while an inactive volcano is the one that has no record of eruption for the last 10000 years and its physical form is being changed by agents of weathering and erosion through formation of deep and long gullies. Scientists classify volcanoes according to how explosively they erupt as well as their height and shape.
The four types of volcanoes they recognize are. Evaluate the statement From a biblical view of history almost all volcanoes are active according to the USGS definition of volcanic activity This statement is true because humans have been around since the beginning and couldve possibly witnessed the eruption. Some volcanic eruptions are explosive and others are not.
The explosivity of an eruption depends on the composition of the magma. If magma is thin and runny gases can escape easily from it. When this type of magma erupts it flows out of the volcano.
A good example is the eruptions at Hawaiis volcanoes. This video describes the features geologists use to classify common types of volcanoes. We compare and contrast the features of two types of large volcanoes.
A volcanologist is a geologist who studies the eruptive activity and formation of volcanoes and their current and historic eruptions. Volcanologists frequently visit volcanoes especially active ones to observe volcanic eruptions collect eruptive products including tephra such as ash or. Cinder cones are the smallest kinds of volcanoes and are formed by bursts of gasses mostly that of pyroclastic material.
Composite cones are volcanoes formed by the ejections of both lava and pyroclastic materials and are larger than cinder cones but much smaller than shield cones. Shield cones are formed by lava and these are the largest volcanoes. Scientists use a wide variety of techniques to monitor volcanoes including seismographic detection of the earthquakes and tremor that almost always precede eruptions precise measurements of ground deformation that often accompanies the rise of magma changes in volcanic gas emissions and changes in gravity and magnetic fields.
The Volcanic Explosivity Index VEI is a relative measure of the explosiveness of volcanic eruptionsIt was devised by Chris Newhall of the United States Geological Survey and Stephen Self at the University of Hawaii in 1982. Volume of products eruption cloud height and qualitative observations using terms ranging from gentle to mega-colossal are used to determine the explosivity value. The general cycle of activity of andesitic and dacitic volcanoes may be described by quiescence phreatic explosive activity with the formation of a new crater and repeated dome building and destruction accompanied by explosions.