Volcanic Hazards and Geological Features Quiz

Volcanic Hazards and Interesting Geological Features

• Pyroclastic flow is one of the deadliest volcanic hazards, as seen in the destruction of Pompeii.
• Volcanoes can still be active and pose a threat to cities, but better monitoring allows for evacuation and potentially saving lives.
• Maurice and Katia Kraft were famous volcanologists who risked their lives to study volcanoes and capture incredible footage.
• Lahars, or volcanic mudflows, can be just as dangerous as pyroclastic flows and can cause erosion and inverted topography over time.
• Volcanic eruptions can cause climate change by blocking out the sun and cooling the Earth.
• The Sutter Buttes in California are an interesting geological feature that formed from volcanic activity and erosion.
• Lahars can solidify and create a cement-like cap that resists erosion and creates inverted topography.
• Inverted topography is when a previously low-lying area becomes a high point due to erosion and the resistance of solidified lahars.
• The Sutter Buttes were once a volcanic complex that has eroded over time, leaving behind the unique shape seen today.
• Volcanic mudflows can originate from melting snow and ice, as well as ash and debris from eruptions.
• The explosive power of volcanoes can be seen in videos of eruptions captured by brave hikers and scientists.
• Understanding volcanic hazards and geological features can help us better prepare for and appreciate the power of nature.

Volcanoes and Igneous Activity

• The Sierra Nevadas and Cascades are examples of mountain ranges formed by magma chambers pushing up and cracking the crust.
• Radiating dikes and volcanic necks are features that cut across or go with the layers caused by eruptions and volcanoes.
• The magma is generated through partial melting and decompression melting caused by water, resulting in lava flows.
• Divergent plate boundaries are a long line of volcanoes, producing the greatest volume of lava and forming pillow basalts.
• Intraplate volcanism occurs when exceptionally hot mantle plumes punch through the crust and form hotspots, such as Yellowstone and Hawaii.
• Hotspots can form a track through land, such as the one in Yosemite.
• Most volcanoes are at convergent plate boundaries, where subduction occurs.
• Oceanic-oceanic plate boundaries form volcanoes such as those in Japan.
• Oceanic-continental plate boundaries form the Andes Mountains and the Cascades.
• Rifting causes volcanoes to form in the East African Rift Valley and the eastern part of the western United States.
• Iceland is an example of volcanoes forming at divergent plate boundaries and hotspots.
• The global distribution of igneous activity is not random, and most volcanoes are at convergent plate boundaries or hotspots.

Igneous Features: Lava Flows, Volcanic Necks, Columnar Basalt, and Intrusive Igneous Activity

• The text describes large lava flows in Oregon, where each layer represents a successive lava flow.
• The lava flows are made of dark rock and have covered the entire area.
• The area has experienced massive fissure eruptions, including the largest extinction event in the planet's history that killed 90% of life on the planet.
• Volcanic necks are remnants of volcanoes that were eroded away, leaving a resistant vent standing.
• Shiprock in New Mexico and Devil's Tower are famous volcanic necks.
• Columnar basalt is an interesting feature that looks like columns stitched together with a hexagonal pattern.
• The hexagonal pattern is created when the lava cools and contracts, breaking into pieces.
• Intrusive igneous activity is defined by its coarse-grained texture and occurs beneath the surface.
• Intrusions are caused by magma making its way through the crust, cracking the ground around it.
• If magma goes across the bedding, it's called a dike, and if it goes with the bedding, it's called a sill.
• Laccoliths occur when magma is forcibly injected between the strata and bows the strata up.
• Batholiths are massive intrusive igneous features, and the Sierra Nevada mountain range is an example of a giant batholith.