What does the ancient earthquake detector do? it help tell the direction of where it came from and the slightest movement will make the ball fall if you are referring to the ancient china one Edit
Depending on the type of lava flow, the resulting rocks look very different. This was a pahoehoe flow. A lava flow is caused by a volcanic eruption. The lava can flow down the volcano at speeds ranging from 1/24 to 50 meters an hour. They can be 1,300 degrees fahrenheit or more. They are very destructive.
Short-term prediction of volcanic eruptions involves monitoring the volcano to determine when magma is approaching the surface and monitoring for precursor events that often signal a forthcoming eruption. 1  Earthquakes-As magma moves toward the surface it usually deforms and fractures rock to generate earthquakes. Lava flows are produced on the surface, and these run like liquids down slope, along the lowest areas they can find. 2  If the magma emerges along a fracture, it results in a fissure eruption, often called a curtain of fire. 3  Lava flows produced by eruptions under water are called pillow lavas.