2How Magma Reaches the Surface Magma rises because magma is less __________ than the surrounding _________ material.It will rise until it reaches the ___________ or becomes trapped beneath _________ of _________.
3A Volcano EruptsA volcano erupts when an opening develops in _________ _________ on the surface.During a volcanic eruption, the _________ dissolved in __________ rush out, carrying the magma with them.Inside a Volcano:__________ ___________ – The pocket beneath a volcano where magma collects
4,The magma moves through the _______, a long tube in the ground that connects the magma chamber to Earth’s surface.__________ - an opening in the volcano where gases and molten rock leave.__________ ________ – The area covered by lava as it pours out of a vent.Crater – A _________-__________ area that may form at the top of a volcano around the volcano’s central _________.
5Characteristics of Magma __________ content, how __________ or _________ the magma is, temperature and silica contents are important factors as to the __________ of a volcanic eruptions.The amount of ___________ in magma helps to determine how easily the magma flows. Silica is formed from the elements ___________ and ___________ and is abundant in the crust and ___________. The __________ silica content in magma the thicker the magma.
6Types of Volcanic Eruptions Silica content determines whether the volcanic eruption is ___________ or ___________.Quiet Eruption:A volcano erupts quietly if its magma flows easily.Quiet eruptions produce two types of lava:________________ – fast-moving, hot lava_____ – cooler, slower moving lava
7Explosive Eruptions:If magma is __________ and __________, a volcano will erupt explosively.The explosion will break the lava into ___________ that quickly cool and harden into pieces of different size called ___________.Smallest pieces are called _________ (fine, rocky particles as small as a grain of sand), ___________ are pebble-sized particles and ___________ are larger pieces that range in size from a baseball to a car.
9Stages of a Volcano____________ – a volcano that is erupting or has shown signs that it may erupt.____________ – sleeping and may become active in the future.____________ – a volcano that is unlikely to erupt again.
10Other Types of Volcanic Activity Hot Spring – forms when ______________ heated by a nearby body of magma rises to the surface and collects in a natural _________.Geyser – a fountain of ___________ and __________ that erupts form the ground._____________ ____________ – water heated by magma that provides a clean, reliable energy source.
11Monitoring VolcanoesGeologists have been somewhat successful in predicting eruptions. They use the same devices that are used to monitor earthquakes (______________, __________-___________ devices, etc.). Geologist will also monitor the small ____________ that normally accompany a volcano.
12Volcano HazardsAlthough quiet eruptions and explosive eruptions involve different volcano hazards, both types of eruptions can cause damage far from the crater’s rim.Volcanic ash can bury entire towns, damage ___________, and car _____________. Eruptions can also cause ___________ and _______________.