Wind carries heat, moisture, pollutants, and pollen to new areas. Many daily weather patterns depend on wind. A coastal region, for instance, undergoes changes in wind direction daily. The sun heats the land more quickly than the water.
Lava flows are the least hazardous of all processes in volcanic eruptions. How far a lava flow travels depends on the flows temperature, silica content, extrusion rate, and slope of the land. A cold lava flow will not travel far and neither will one that has a high silica content. Such a flow would have a high viscosity<span> (a high resistance to flow). A basalt flow like those in Hawai'i have low silica contents and low viscosities so they can flow long distances. Such a flow can move as far away as 4 km from its source and have a thickness of 10 m (Bryant, 1991). These flows can move at rates of several kilometers per hour (Scott, 1989). </span><span>More silica-rich flows can move as far away as 1.3 km from their sources and have thicknesses of 100 m (Bryant, 1991). These flows can move at rates of a few to hundreds of meters per hour (Scott, 1989). If a lava flow is channelized or travels underground in a lava tube then the distance it travels is greatly extended.</span>
Because light travels more than 800 thousand times as fast as sound does.
