Lava flows

Definition

Lava flows are streams of molten rock that emerge from a volcanic eruption, spreading across the landscape as they cool and solidify. These flows can vary significantly in speed, temperature, and composition, influencing their potential impact on the surrounding environment. Understanding lava flows is essential for assessing volcanic hazards, studying intraplate volcanism, and preparing communities for possible eruptions.

5 Must Know Facts For Your Next Test

1. Lava flows can be classified into two main types: Pāhoehoe, which is smooth and ropy, and ʻaʻā, which is rough and jagged.
2. The speed of lava flows can range from less than 1 meter per hour to over 100 meters per hour, depending on factors like slope and viscosity.
3. Lava flows can reach temperatures between 700°C and 1,200°C (1,292°F to 2,192°F), which can incinerate anything in their path.
4. Geologists use lava flow morphology to assess the history of volcanic activity and predict future eruptions by analyzing the landscape changes they create.
5. The proximity of communities to active volcanoes greatly influences their risk level from lava flows, making local preparedness and awareness essential.

Review Questions

• How do different types of lava flows affect volcanic risk assessment methodologies?
  • Different types of lava flows, such as Pāhoehoe and ʻaʻā, present varying risks due to their physical characteristics. Pāhoehoe flows are smoother and can cover large areas with lower hazard potential initially, while ʻaʻā flows are more chaotic and can create barriers that cause pooling of lava. Understanding these differences helps in evaluating potential impacts on communities and infrastructure during risk assessment processes.
• Evaluate the role of lava flows in intraplate volcanism and hotspots within the Earth's crust.
  • Lava flows originating from hotspots contribute significantly to our understanding of intraplate volcanism by revealing how molten rock rises through the mantle to create volcanic islands like Hawaii. These islands often have extensive lava flow fields that provide insights into the eruption history and volcanic processes at play. The composition of the lava also informs scientists about the mantle's characteristics and the dynamics of hotspot activity.
• Synthesize community preparedness strategies that incorporate knowledge about lava flows in regions near active volcanoes.
  • Effective community preparedness strategies should include comprehensive education on the behavior of lava flows, which allows residents to understand risks specific to their area. This can involve creating evacuation plans, conducting regular drills, establishing communication networks during eruptions, and providing resources for property protection measures. By integrating scientific knowledge about lava flow characteristics into community planning efforts, areas near active volcanoes can enhance their resilience to future volcanic events.

Related terms

Basalt:

A common type of volcanic rock that typically forms from low-viscosity lava flows, allowing them to travel long distances before cooling.

Pyroclastic flow: A fast-moving current of hot gas and volcanic matter that can occur during explosive eruptions, posing a significant threat to life and property.

Viscosity:

A measure of a fluid's resistance to flow; in volcanology, it affects how easily lava can move and how far it can travel from the eruption site.