Volcanic Eruption Process and Types of Volcanoes

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What is the characteristic of lahars when they are most dangerous?

When they are dry and powdery

When they are wet and fluid (correct)

When they are cold and solid

When they are hot and fluid

What is the primary reason why ash fall poses a great danger to airplanes?

Ashes can cause visibility problems

Ashes can block sunrays

Ashes can interfere with the plane's engines (correct)

Ashes can cause climate cooling

What is the result of excessive ash fall on crops?

Crops grow faster

Crops become more fertile

Crops are destroyed (correct)

Crops are unaffected

What is the term used to describe the collective materials that come out of the volcano's mouth during an explosive eruption?

Pyroclastic Flow Signup and view all the answers

What is the effect of ash fall on the environment?

It causes both breathing problems and climate cooling Signup and view all the answers

What is the composition of ash fall?

Fine-grained volcanic materials Signup and view all the answers

What is the term for molten materials that come out of the surface during a volcanic eruption?

Lava Signup and view all the answers

How are active volcanoes classified by PHIVOLCS?

Erupted within historical times and have documented records Signup and view all the answers

What is the term for a type of mudflow or debris flow that forms when pyroclastic materials mix with rainwater or water from a volcano's crater lake?

Lahar Signup and view all the answers

What is the term for various forms of matter ejected by a volcano during its eruption?

Pyroclastic materials Signup and view all the answers

What is the term for a vent on the earth's crust where magma moves up from the depths of the earth to its surface and into the atmosphere?

Volcano Signup and view all the answers

What type of volcano has a physical form that is being changed by agents of weathering and erosion?

Inactive volcano Signup and view all the answers

What is radon?

A type of noble gas Signup and view all the answers

What occurs prior to an earthquake event?

An increase in radon emissions in soils and groundwater Signup and view all the answers

What is the term used to describe a series of mild local movements that occur frequently at short periods of time at almost similar depths?

Swarms Signup and view all the answers

What is the main difference between landslides and slope failure?

The type of process involved (mass-wasting or failure) Signup and view all the answers

What is an aquifer?

A type of rock that contains groundwater Signup and view all the answers

What is the purpose of studying earthquake trends?

To predict when the next big earthquake will occur Signup and view all the answers

What is the primary cause of seismic waves during an earthquake?

The release of energy stored in the earth's rocks Signup and view all the answers

What is the term used to describe the breaking or fracture of the earth's surface or rocks?

Ground rupture Signup and view all the answers

What is the result of the increase in water pressure in the soil during an earthquake?

The reduction of effective stress between solid particles Signup and view all the answers

What is the term used to describe the process of the ground sinking or developing a depression due to liquefaction?

Subsidence Signup and view all the answers

What is one of the effects of liquefaction?

Ground subsidence Signup and view all the answers

What can be formed as a result of the process of subsidence?

Lakes Signup and view all the answers

What is the maximum speed that pyroclastic flows can travel?

700 kph Signup and view all the answers

What is the temperature range of rocks and gas inside pyroclastic flows?

200°C to 700°C Signup and view all the answers

What is the primary factor that affects the direction of pyroclastic flows?

The topography of the surrounding area Signup and view all the answers

What is the term used to describe the turbulent rush of pyroclastic materials above the pyroclastic flow?

Pyroclastic surge Signup and view all the answers

What is the minimum size of rock fragments that are classified as blocks or bombs?

64mm Signup and view all the answers

What was the approximate number of inhabitants killed when Mt. Pelee erupted on May 8, 1902?

30,000 Signup and view all the answers