Penny Major age 8 Toronto Ont,.
What causes earthquakes?
Every person likes to build with building blocks. Sometimes the building stands firm and solid. Once in a while you male a building that comes tumbling down. You may only sneeze or it may Oven topple over by itself. Down tumble the blocks into a jumbled pile. The blocks in the pile slip and slide a bit and finally settle down. This is a very small copy of a trembling earthquake.
Under our feet, the ground is made of hard rocks. In many places the layers are broken into slabs and chunks and pushed out of place. There may be a great slab, big as a mountain, balanced on another great slab. There may be a long ridge big as a range of mountains, shoving over a thinner, weaker layer of rock. In most places, the ground under our feet is parked in firm orderly layers. In a few places the chunks, slabs and layers of rock are jumbled all higgledy piggledy.
The old earth likes to have things neat, Sooner or later she gets around to tidying up those topsy‑turvy slabs of rock under the ground, She gives them a shake and they go tumbling and rumbling around. The ground trembles and we got an earthquake. Sometimes the upset below even cracks the surface of the ground. The old earth is trying to arrange her outside blanket of rocks so that the weight is even all over.
An earthquake happens miles below our feet. But this is actually near the surface of the huge earth. As you know there is solid ground under our feet for almost 8000 miles. This is way through to China on the other side of our round globe, Earthquakes happen only in the surface crust of the earth which is about 50 miles deep, Below this crust of slabs and layers the earth keeps her rocks in solid$ orderly formation,
The crusty blanket however often get rumpled, Mountains bulge up and bend the rocky crust and sometimes crack it. Rain snow and wind wear down their sharp noses and pile tons of rock and dirt in other places, This upsets the weight of the earth's crusty blanket. Certain areas become weak and strained.
Sooner or later, the earth gives a shrug and the rocky layers go tumbling around. They make an earthquake as they straighten themselves out.
We know where these weak spots in the earths crust are. There is one where the Pacific Ocean meets the shores of North and South America, The massive Rockies and the tall Andes had something to do with upsetting the rocky layers in the area. There is another weak belt through Japan and Indonesia; There is another around the rim of the high Himalayas. These weak areas under the deep ground are the worlds earthquake zones, They are places where high mountains have piled up topsy‑turvy buildings of rocky slabs. Most of the worlds volcanos are also found in these regions. And here the earth often shrugs her crusty blanket and makes the ground tremble and quake beneath our feet,