Question

Classify the volcano Fuji, which has steep sides and is made of layers of silica-rich lava and ash.

Short answer

Mount Fuji is a composite (stratovolcano) volcano.

Step-by-step solution

Identify Volcano Characteristics

Examine the given characteristics of the volcano. It has steep sides and is composed of alternating layers of silica-rich lava and ash.

Match Characteristics to Volcano Types

Compare these characteristics to common volcano types. Composite or stratovolcanoes typically have steep sides and are formed from layers of lava and ash.

Confirm with Additional Information

Consider that Fuji is a well-known example of this type, often cited in many geological studies as a classic stratovolcano.

Final Classification Decision

Based on the characteristics and confirmation, classify Mount Fuji as a composite volcano, also known as a stratovolcano.

Key concepts

Stratovolcano

A stratovolcano, also known as a composite volcano, is one of the most famous types of volcanoes. These volcanoes are characterized by their tall, steep profiles and are often very picturesque. A stratovolcano is formed by multiple layers of hardened lava, tephra, pumice, and volcanic ash. This layered structure is what gives the stratovolcano its steep, conical shape.

Stratovolcanoes can be found around the world and are typically associated with volcanic arcs and tectonic plate boundaries. This is due to subduction zones, where one plate moves underneath another, leading to volcanic activity.

• Well-known examples include Mount Fuji in Japan, Mount St. Helens in the United States, and Mount Vesuvius in Italy.
• They can produce explosive eruptions due to the high gas and silica content in the magma.
• Stratovolcanoes are composed of both lava flows and fragmented materials such as ashes.

Lava Layers

In a stratovolcano, layers of lava play a crucial role in building its structure. These layers are formed during eruptions when molten rock, known as lava, flows out of the volcano and cools down.

The lava in stratovolcanoes is often silica-rich, meaning it has a high silica content. This makes the lava more viscous or sticky compared to basaltic lava found in shield volcanoes. Because of its high viscosity, the lava doesn't flow very far, leading to the steep sides characteristic of stratovolcanoes.

• Lava layers build up over time as repeated eruptions occur, each adding new layers of solidified magma.
• These layers are one reason why stratovolcanoes are so towering and steep.
• Due to their composition, the lava layers can trap gases, potentially leading to explosive eruptions.

Ash Deposits

Ash deposits are another significant feature of stratovolcanoes. When a stratovolcano erupts, it might not only release lava but also spew enormous clouds of volcanic ash into the air.

Volcanic ash is made up of tiny minerals, rock fragments, and volcanic glass created during explosive eruptions. This ash can be carried by the wind and settle over a vast area, often leading to thick layers of ash deposits on and around the volcano.

• Ash deposits are formed through the explosive dispersion of mineral particles during an eruption.
• These deposits add to the layering of the volcano, contributing to its composite nature.
• The heavy ash fall can impact local climate and ecosystems, and is hazardous to aviation.