Unit 9 - Page 272 - 276

What type of volcanic eruption is characterized by gently sloping shield volcanoes (Hawaiian type)?

• Explosive eruptions with tephra clouds

• Lava flows with high viscosity

• Non-explosive eruptions with fluid lava flows

• Eruptions producing large pyroclastic flows

Answer explanation

• Explanation: These volcanoes are broad and not steep because the lava is runny, like pancake batter spreading out.

• Example: Mauna Loa in Hawaii is a famous shield volcano.

Which type of volcano is associated with explosive eruptions and steep slopes?

• Shield volcanoes

• Cone-shaped volcanoes (Plinian type)

• Hawaiian volcanoes

• Icelandic volcanoes

Answer explanation

• Explanation: These volcanoes erupt violently, throwing ash and rocks into the air, which stack up to create a steep cone shape.

• Example: Mount Vesuvius in Italy, which buried Pompeii.

What type of lava flow is characterized by a rough, jagged surface?

• Aa flow

• Pahoehoe

• Basaltic flow

• Fissure flow

Answer explanation

• Explanation: Think of broken-up rocks being pushed by a bulldozer. That’s what Aa lava looks like.

• Example: Lava flows on Mount Etna in Italy often have Aa characteristics.

Which type of lava flow has a smooth, rope-like texture?

• Aa flow

• Pahoehoe

• Andesitic lava

• Tephra flow

Answer explanation

• Explanation: The lava moves like thick syrup and forms smooth, wavy patterns as it cools.

• Example: Lava from Kilauea in Hawaii frequently forms Pahoehoe patterns.

Which of the following is true about active volcanoes?

• They have not erupted for thousands of years

• They have no record of past eruptions

• They are currently erupting or are likely to erupt

• They only occur near mid-ocean ridges

Answer explanation

• Explanation: These volcanoes are like a firework that hasn’t exploded yet – you know something is likely to happen.

• Example: Mount St. Helens in the USA is an active volcano.

What term is used for volcanoes that have not erupted in a long time but may erupt again?

• Active volcanoes

• Extinct volcanoes

• Dormant volcanoes

• Icelandic volcanoes

Answer explanation

• Explanation: These are “sleeping” volcanoes, like a bear hibernating – inactive now, but they might wake up.

• Example: Mount Fuji in Japan is dormant.

What term describes volcanoes that are unlikely to erupt again?

• Dormant volcanoes

• Extinct volcanoes

• Shield volcanoes

• Plinian volcanoes

Answer explanation

• Explanation: These are like old, worn-out batteries that can’t be used anymore.

• Example: Arthur’s Seat in Scotland is an extinct volcano.

What is the primary hazard associated with tephra clouds?

• Formation of lava flows

• Heavy rain and mudflows

• Ashfall and damage to aircraft

• Rising sea levels

Answer explanation

• Explanation: Ash from a volcano can get into airplane engines and cause them to stop working.

• Example: The 2010 Eyjafjallajökull eruption in Iceland disrupted flights across Europe.

What is a characteristic feature of pyroclastic flows (nuees ardentes)?

• Slow-moving lava flows

• Extremely hot and fast-moving clouds of gas and ash

• Rope-like lava textures

• Eruptions limited to undersea volcanoes

Answer explanation

• Explanation: Imagine a burning avalanche traveling at hurricane speeds – that’s a pyroclastic flow.

• Example: Mount Pelee’s eruption in 1902 wiped out the town of Saint-Pierre in Martinique.

Which hazard is associated with ash fallout?

• Landslides on volcano slopes

• Contamination of water supplies and air pollution

• Submarine eruptions

• Formation of shield volcanoes

Answer explanation

• Explanation: When ash falls from the sky, it can block sunlight, damage plants, and make it hard to breathe.

• Example: The 1991 Mount Pinatubo eruption in the Philippines caused widespread ash fallout.