What are the 2 types of lava flow?

What are the 2 types of lava flow?

Lavas, particularly basaltic ones, come in two primary types: pahoehoe (pronounced ‘paw-hoey-hoey”) and aa (pronounced “ah-ah”). Both names, like a number of volcanological terms, are of Hawaiian origin. A third type, pillow lava, forms during submarine eruptions.

How thick is lava flow?

Based on studies of lava flow cooling rates, it will take more than 130 days for a flow this thick (about 4.5 m, or 15 ft) to cool to a temperature of about 200 degrees Celsius (290 degrees Fahrenheit). (Credit: A. Lerner, USGS. Public domain.)

Which type of lava is more viscous?

Viscosity of Magmas Thus, basaltic magmas tend to be fairly fluid (low viscosity), but their viscosity is still 10,000 to 100,0000 times more viscous than water. Rhyolitic magmas tend to have even higher viscosity, ranging between 1 million and 100 million times more viscous than water.

Which lava is more viscous?

What is blocky lava flow?

A surface flow of hot, molten lava covered in a carapace of crystalline, angular blocks which tend to be smoothly faceted and may have dimensions up to several metres. Blocky lava morphology is usually confined to lavas of high viscosity and intermediate to high silica contents.

What is thick lava called?

Discern the difference between pahoehoe and aa volcanic lava flows at Kilauea, Hawaii. Lava flowing toward the sea from Kilauea volcano, Hawaii, takes two recognizable forms: fast-flowing, ropy lava, called pahoehoe, and thick, blocky lava, called aa.

What are lava flows?

Lava flows are streams of molten rock that pour or ooze from an erupting vent. Lava is erupted during either nonexplosive activity or explosive lava fountains. But when basalt lava flows are confined within a channel or lava tube on a steep slope, the main body of the flow can reach velocities >30 km/h (19 mph).

Which type of magma is the least viscous?

basaltic magmas
Thus, basaltic magmas tend to be fairly fluid (low viscosity), but their viscosity is still 10,000 to 100,0000 times more viscous than water.

Which is a smooth and continuous lava crust?

Pahoehoe is a smooth and continuous lava crust. Pahoehoe forms when the effusion rate is low and consequently the velocity of lava flow is slow 2. Pahoehoe lava flow is usually at least 10 times slower than typical aa lava flow 5. Higher effusion rate results in lava flow being shattered which is how the rubbly and clinkery aa lava surface forms.

Which is an intermadiate stage of the lava formation process?

The formation process of basaltic ropy pahoehoe lava. Coulée is a volcanic landform which is an intermadiate stage between lava dome and lava flow. The lava that forms coulée is too thick to flow like a normal lava flow.

How are blocky lava flows different from regular lava flows?

Blocky flows are common if the silica content of lavas is higher (composition of basaltic andesite to rhyolite) 5. Blocky lava flows resemble aa lavas. They also have highly irregular surfaces covered with debris, but they contain larger lava blocks with smoother sides and angular edges with common dimensions from few decimeters to several meters.

Which is the most dangerous part of a lava flow?

Generally speaking, smaller lava lobes are safer and larger gently sloping, but otherwise relatively smooth parts are the most dangerous ones. This image shows also that voids in lava flows are a common feature. Such a long tunnel-like caves are called lava tunnels.