Search results
Results from the WOW.Com Content Network
A volcanic plug, also called a volcanic neck or lava neck, is a volcanic object created when magma hardens within a vent on an active volcano. When present, a plug can cause an extreme build-up of high gas pressure if rising volatile -charged magma is trapped beneath it, and this can sometimes lead to an explosive eruption.
After magma is generated, it will travel across the crust and lead to the formation of magma conduits and chambers. In continental crust, partial melting occurs when a portion of the solid rock melts into felsic magma. [4] Rocks in the lower crust and the upper mantle are subject to partial melting.
Volcanic necks are feeder pipes for volcanoes that have been exposed by erosion. Surface exposures are typically cylindrical, but the intrusion often becomes elliptical or even cloverleaf-shaped at depth. Dikes often radiate from a volcanic neck, suggesting that necks tend to form at intersections of dikes where passage of magma is least ...
Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks .
Morro Rock (Salinan: Le'samo; Chumash: Lisamu'; Spanish: El Morro) [4] [5] [6] is a volcanic plug in Morro Bay, California, on the Pacific Coast at the entrance to Morro Bay harbor. A causeway connects it with the shore, making it a tied island. The rock is protected as the Morro Rock State Preserve. [7]
A.D. 79: Mount Vesuvius, Italy. Mount Vesuvius has erupted eight times in the last 17,000 years, most recently in 1944, but the big one was in A.D. 17. One of the most violent eruptions in history ...
Although volcanic eruptions pose considerable hazards to humans, past volcanic activity has created important economic resources. Tuff formed from volcanic ash is a relatively soft rock, and it has been used for construction since ancient times. [96] [97] The Romans often used tuff, which is abundant in Italy, for construction. [98]
Over 400 earthquakes have been detected beneath Washington's Mount St. Helens in recent months, though there are no signs of an imminent eruption.