Lava is molten rock. Meaning, the temperature created must be extremely high -- high enough to melt rock. Therefore, if a person is covered by lava, it would be the same process as cremation-- the body would burn until it returned to an "ash" form.
In volcanic eruption, the air fills with hot gasses and ashes. Many of the gasses can kill when inhaled. Also, ash can suffocate. As well, in history, some civilizations have been buried in the white-gray ash. Whether inhaled or a person is buried in ash, suffocation would result.
Very, very few people survive after a major volcanic eruption with heavy ash and wide lava flows. In one volcanic explosion in 1815, on tiny island called Sumbawa (near Java), stands the volcano Tambora (today called Mount Tambora). The first eruption was ranked a 7 on the Volcanic Explosivity Index (VEI). That first major explosion on April 5, 1815 released 200 million tons of sulphur dioxide and 100 cubic km of rock. The provinces of Pekat and Tambora were completely buried. Gases, extreme heat, lava, and ash immediately suffocated and incinerated people, then buried the entire village. This was followed by a second eruption on April 10th 1815, which buried the village known as the Kingdom of Tambora under 10 feet of ash, immediately killing 10,000 victims in its path. Another source puts the death toll much higher. The Tambora people became extinct.
Other people who survived near the village of Tambora ran toward the ocean. But few people could outrun the poisonous gasses, and lava running into the ocean turned peaceful fishing waters into a boiling cauldron closest to land. The island, which once supported farming and trading, was in ruins. Crops had been buried and now nothing grew on ash or cooled lava pathways. Survivors sold themselves into slavery to passing ships, just so they could get food by working on the ship. Parents or relatives gave up their children and placed them into slavery with ships' captains so the children could eat and survive.
A geologist has been investigating the island for several decades, and has uncovered some of the villages. The remains of two adult victims, suffocated and buried during the blast, were found in 2004. As seen in other areas where a volcano produced a catastrophic eruption, researchers find whole villages of people killed where they stood, sat, or had been lying at the time. For example, one family had been sleeping when the volcano erupted and they were found, lying on their sides, with the man's arm draped over his wife's body ("spooning") with their small child lying in front of his mother.
So, once again, the answer to your question is people who are closest to a large eruption are incinerated or suffocated and buried in ash. People who are at a distance may suffer burns (from air heat and lava) or lung / breathing problems (from the ash / gas).
You can read more about Tambora through the Related Link, under "the Summer that never was".
lava shoots out of the top
"lava"
The molten lava solidifies into solid rock on cooling.
it makes is cool and react
Flood basalts is the term to describe a flow of fluid basaltic lava that issues from cracks or fissures. It commonly covers an extensive area of thickness of hundreds of meters.
lava shoots out of the top
"lava"
lichens
The molten lava solidifies into solid rock on cooling.
lava melts and then soldifies and turns into rocks:L
When water meets a lava 'block', the lava is converted into an obsidian block. If water meets 'flowing' lava then the lava is turned into cobblestone.
When lava flows reach the sea, the lava rapidy cools to form an igneous rock.
Lava at the top of a volcano will generally flow downhill.
On contact with water lava will cool rapidly to form rock.
when the lava rock is in the volcanoe it is magma, and when it reaches the outside of the volcanoe it is lava.
The typical cone shape of a volcano happens when sticky lava erupts upward. Sticky lava creates a dome shape and the lava cools slowly.
it explodes