Tectonic Plates, Earthquakes, and Volcanos

Tectonic Plates Map
Tectonic Plates Map

Yesterday (April 5, 2018) there was a magnitude 5.3 earthquake off the coast of California near Los Angeles. No serious damage resulted, but scientists say there is a one-in-twenty chance that quake could be the foreshock of a larger quake. This brings up the question of why we have earthquakes. Did God do a poor job of designing the Earth?

The answer to that question is, “No.” Earthquakes result from factors that are essential for life on Earth. Earth’s crust consists of tectonic plates floating on the mantle, which is a region of molten rock. Under the continents, the Earth’s crust averages 18 miles (30 km) thick. Under the oceans, the crust is only about 3 miles (5 km) thick. The mass of the crust puts great pressure on the molten rock in the mantle causing it to be very viscous. If a crack opens in the crust, the molten rock will move upward, become more liquid as it is under less pressure. Then it may burst from the surface creating a volcano.

Volcanoes create mountains, and so does the movement of the tectonic plates. The tectonic plates moving against each other also produce earthquakes. Sometimes the plates will move against each other horizontally. We call that a slip-strike earthquake and that is what happens in the San Andreas fault in California. The quake that just occurred was a thrust quake where one side of a fault thrusts over the top of the one next to it. The Rocky Mountains and the Himalayas were pushed up by movement of the tectonic plates.

By the creation of mountains, the Earth has been continuously renewed. On the surface of the continents, erosion, and weathering break up solid rock to produce sand, clay, and ultimately topsoil. Erosion cuts down the mountains and deposits sediment in the lower elevations. Further erosion carries the sediment out into the oceans. In the deepest parts of the ocean, there are trenches. Huge amounts of sediment settle into those trenches, but they never get full. That’s because the sediment sliding into the trenches is finding its way down into the mantle.

The movement of sediment replenishes the mantle with new material which then resupplies the continents with new rock. Volcanoes erupt bringing recycled minerals and nutrients to the surface. Volcanic soils are the richest soils on Earth. This system has also brought the iron and other essential minerals into the Earth’s crust.

This is a greatly oversimplified explanation of the comprehensive recycling system that God designed into the planet on which we live. Earthquakes and volcanoes are destructive when humans build homes and cities close to the fault lines and active volcano sites. But if the Earth’s recycling system didn’t exist, erosion would eventually reduce the land masses to sea level, and Earth would be a water world.
–Roland Earnst © 2018

Doomsday Predictions Misguided

Doomsday Predictions
Just about every day you will see a headline in some periodical saying that the world will soon end in catastrophe. These doomsday predictions come from tabloids and church bulletins and always bring some kind of data to support them. Religious periodicals usually quote from Revelation and tabloids will take something out of context from a scientist or political figure.

The fact is that the major possible causes of global catastrophe do not come from periods of unusual natural activity. Earthquake numbers for the past ten years have been much smaller than 50 years ago. Hurricane frequency and intensity are not higher than in the past, although human mismanagement of shorelines has increased the damage even a small hurricane can produce.

The Sun is not becoming more active. The current cycle of solar activity is the lowest it has been in 100 years. In 1990 solar activity peaked at almost 300 sunspots. In the next maximum which happened in 2000, there were just over 200 sunspots. The last cycle which was in 2014, had 100 sunspots. In the December 2017 issue of Astronomy magazine, the lead article by Bruce Dorminey (page 20) is titled “Why Has the Sun Gone Quiet.” He suggests that the Sun will be relatively quiet for a long time.

In spite of the doomsday predictions, the biggest threat to our survival does not come from the natural world. God has designed a world that is remarkably stable. Earthquakes, hurricanes, and solar activity may cause problems, especially where humans have built vulnerable structures and removed natural safeguards, but our greatest danger is from each other. Our biggest problems come from humans refusing to do what Jesus told us would lead to our safety and security now and in eternally. You can read about it in the “Sermon on the Mount” recorded in Matthew chapters 5-7.
–John N. Clayton © 2017