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>
Answer: Africa includes the rich source of water drainage in the form of rivers.
Explanation:
The course travelled by the major rivers in Africa are as follows:
1. Congo: Center to north and further to the Western region finally drains into the Atlantic Ocean.
2. Nile: Northeastern part to the North and then finally to the Mediterranean Sea.
3. Zambezi: South eastern to Indian Ocean.
4. Niger: West to the Guinea Gulf.
The waves crash into the sand, sometimes creating dunes, and it can also wash some sand out into the ocean. Hope this helps!
