1.   The great mobility of these pyroclastic flows is attributable to the volume of hot gas present and the heating of engulfed air which renders the solid material highly buoyant.

2.   As a result of their great mobility pyroclastic flows can generate pyroclastic flow deposits, or ignimbrites, which cover a large area.

3.   We have already noted how certain kinds of highly explosive eruptions can produce massive pyroclastic flows which create sheets of ignimbrite.

4.   The dome atop the volcano is glowing red and occasional pyroclastic flows add to the debris on the south end of the island.

5.   The pyroclastic zone, also known as the pyroclastic flow, was created where hot pumice poured out of the volcano sterilizing the earth.

6.   Pyroclastic flows are the result of explosive eruptions of molten or solid rock fragments, or both.

7.   An increase in the size of the pyroclastic flows could force a long-term closure of the airport, he said.

8.   At night, from a safe distance, glowing pyroclastic flows can be seen careening down the slopes of the Soufriere Hills volcano like tumbling fire.

9.   Eruptions are normally preceded by earthquake activity or smaller pyroclastic flows, but this one occurred with no advance warning, Norton said.

10.   In the open, they found the fourth, a victim overtaken by one of the deadly rivers called pyroclastic flows.