Lava is defined as molten or partially molten rock that has been expelled onto the surface of a planet or moon.

Carbonatite lavas are an example of non-silicate lava.

Most molten lavas erupt at temperatures between 800 and 1,200 degrees Celsius.

What is the primary definition of lava as presented in the source material?

What is the typical temperature range for the eruption of most lavas?

Which of the following is cited as an example of a non-silicate lava?

Solidified lava on Earth's crust is predominantly composed of silicate minerals.

Petrologists commonly express lava composition using weight fractions of the oxides of major elements, excluding oxygen.

Higher silica content in silicate lavas leads to higher viscosity.

The viscosity of felsic lava is significantly higher than that of water.

Alkaline lavas are characterized by elevated alkali metal oxide content.

The viscosity of most lava is significantly lower than that of water.

Which factor is identified as the dominant determinant of the physical behavior and viscosity of silicate lavas?

How does the silica content of lava influence its viscosity?

How do petrologists typically characterize the chemical composition of silicate lava?

Felsic lavas have a silica content typically above 63%.

Felsic lavas, due to their high viscosity, usually erupt explosively.

Intermediate lavas contain between 52% and 63% silica.

Intermediate lavas are typically less viscous and erupt at slightly lower temperatures than felsic lavas.

Mafic lavas have a silica content ranging from 45% to 52%.

Ultramafic lavas like komatiite are rare in modern volcanic activity because the Earth's mantle has cooled.

Intermediate lavas are typically found forming features like andesite domes and block lava flows on composite volcanoes.

Ultramafic lavas like komatiites erupted at very high temperatures, around 1,600 degrees Celsius.

Which lava classification is characterized by the highest silica content and consequently the greatest viscosity?

What is the primary reason cited for the rarity of modern ultramafic lavas such as komatiite?

Considering their typical silica content, which of the following lava types would likely exhibit the lowest viscosity?

What is the primary reason cited for the rarity of modern ultramafic lavas?

Pāhoehoe lava is characterized by a smooth, billowy, or ropy surface.

'A'ā lava surfaces are typically rough and rubbly.

Pāhoehoe lava can transform into 'a'ā lava as its viscosity increases.

Block lava flows are covered in smooth-sided, angular blocks, unlike the sharp clinkers of 'a'ā flows.

Pillow lava forms when lava erupts underwater or enters the ocean.

Lava tubes can transport lava for many kilometers before solidifying.

Which type of basaltic lava is characterized by a smooth, billowy, or ropy surface texture?

What is the distinguishing characteristic of block lava flows compared to 'a'ā flows?

Under what conditions does pillow lava typically form?

Which of the following describes a characteristic surface feature of 'a'ā lava?

The low viscosity of mafic lavas allows them to form broad, low-profile shield volcanoes.

Shield volcanoes are typically formed by low-viscosity mafic lavas.

Calderas are typically formed by the collapse of a volcano's summit after a large eruption empties the magma chamber.

A kīpuka is an area of older, vegetated land isolated by surrounding recent lava flows.

Lava tubes are tunnel-like conduits formed when the surface of a relatively fluid lava flow cools and solidifies, creating an insulating crust.

Lava lakes are formed when lava pools within a volcanic crater and remains molten, not necessarily erupting continuously.

Lava deltas are formed when lava flows into a body of water, building new land.

Lava spines are steep, pointed protrusions formed by highly viscous lava.

What type of volcanic structure is commonly formed by low-viscosity mafic lavas?

What is the definition of a kīpuka within a volcanic landscape?

What are lava spines, and what type of lava forms them?

What type of lava is typically associated with the formation of lava spines and domes?

The insulating crust that forms on lava flows impedes the cooling of the interior lava.

Columnar jointing occurs in lava flows due to contraction during cooling.

Vesicles in lava are cavities formed by escaping gases during cooling.

Flow banding is a phenomenon primarily observed in felsic lava flows.

A lava fountain involves the forceful but non-explosive ejection of lava.

Lava flows are primarily hazardous due to their destructive nature to property and infrastructure.

Lava benches are unstable landforms created by lava flows entering the sea.

Wearing sturdy, closed-toe footwear, such as hiking boots, is recommended when traversing recent lava flows for safety.

Diverting lava flows is extremely difficult but has been partially achieved in some instances, such as in Iceland.

Tephra, such as volcanic ash, poses a hazard by burying towns.

Explosive eruptions are typically associated with highly viscous lavas that trap gases.

Entablature refers to irregular, downward-splaying fractures in the upper part of basaltic lava flows, distinct from the regular colonnade below.

Laze is a type of volcanic smog (vog) formed by sulfur dioxide reacting with the atmosphere.

Vog is primarily composed of sulfur dioxide reacting with atmospheric components.

The highest recorded lava fountain occurred at Mount Etna in 2013.

Direct casualties from lava flows are relatively rare, as flows are often slow enough for escape, though exceptions exist.

The Kilauea Iki lava lake provides evidence for the slow cooling of lava because its insulating crust traps heat.

Lava flows that enter the sea can create lava deltas, but also unstable lava benches.

How does the insulating crust of a lava flow influence the state of its interior?

What geological feature arises from thermal contraction and subsequent fracturing within cooling lava flows?

What are vesicles, as observed within solidified lava?

What is the primary hazard associated with lava benches formed by marine lava flows?

What safety precautions are recommended when traversing areas with recent lava flows?

What is the phenomenon known as 'vog'?

What is the primary danger posed by tephra, such as volcanic ash, ejected during volcanic eruptions?

Which type of volcanic eruption is typically associated with less viscous lavas?

What is the 'colonnade' feature within a solidified lava flow?

What specific hazard is associated with lava flows entering the sea, beyond the formation of lava deltas?

What are the potential consequences when a lava flow encounters the ocean?

What is the principal difference between effusive and explosive volcanic eruptions concerning the behavior of lava?

Which factor is most crucial for maintaining the molten state of the lava's interior beneath its crust?

The term 'lava' is believed to have originated from the Italian word, possibly derived from the Latin 'labes,' meaning 'fall' or 'slide.'

What is the etymological origin of the term 'lava'?