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What are ballistics in the context of volcanic eruptions?
What are ballistics in the context of volcanic eruptions?
Ballistics are fragments of magma and old rocks ejected during explosive eruptions, traveling on cannonball-like trajectories.
What is the typical range of ballistic fragments during a volcanic eruption?
What is the typical range of ballistic fragments during a volcanic eruption?
The typical range of ballistics is a few hundred metres to 5 km, but they can exceed 10 km in powerful explosions.
How does the size of pyroclasts compare to ballistics?
How does the size of pyroclasts compare to ballistics?
Pyroclasts can vary in size and include blocks and bombs larger than 64 mm, which may also be entrained within volcanic plumes.
What is the primary hazard associated with ballistic fragments?
What is the primary hazard associated with ballistic fragments?
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What factors influence the distance that ballistics can be thrown during an eruption?
What factors influence the distance that ballistics can be thrown during an eruption?
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How are numerical models used in the study of ballistic dispersal?
How are numerical models used in the study of ballistic dispersal?
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What are the typical terminal velocities of ballistics as they slow down during flight?
What are the typical terminal velocities of ballistics as they slow down during flight?
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What defines a ballistic fragment's trajectory in comparison to a pyroclast?
What defines a ballistic fragment's trajectory in comparison to a pyroclast?
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Study Notes
Ballistics in Volcanic Eruptions
- Ballistics are fragments of magma and pre-existing rocks ejected during explosive eruptions.
- They travel at variable velocities and angles, not within the volcanic plume.
- They are dispersed near the vent, typically within 5 km.
- Ballistics range in size from centimeters to several meters.
- The range can be several hundred meters to 5 km, although some are thrown over 10 km in large explosions.
- Some large fragments (bombs and blocks >64 mm) can be entrained in the plume and travel further.
- These fragments, including all sizes, are called pyroclasts.
- Models are used to predict ballistic dispersal patterns.
Primary Hazards
- High kinetic energy makes ballistics hazardous to people, buildings, and infrastructure.
- Ejected at speeds over 300 m/s but terminal velocity slows them to <150 m/s, depending on their size.
- Impact energy is significant and controlled by ballistic size.
- Can penetrate reinforced concrete.
- Lava fragments can reach 1100°C, retaining enough thermal energy to ignite material on impact.
Secondary Hazards
- Can cause fatalities by collapsing roofs or damaging infrastructure (roads, power lines).
- May ignite flammable materials (vegetation, wood).
- Powerful explosions can create shockwaves and infrasound capable of damaging windows and equipment (electronic doors) at distances of several kilometers.
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Description
Explore the fascinating world of ballistics during volcanic eruptions. This quiz covers the types of volcanic fragments, their dispersal patterns, and primary hazards associated with their explosive ejection. Understand the impact of these geological phenomena on the environment and human safety.
