The Origin of Ocean Trenches, Earthquakes, and the Ring of Fire
SUMMARY: Ocean trenches, some thousands of miles long and several miles deep, lie on the floor of the western Pacific, directly opposite the center of the Atlantic. The plate tectonic theory claims that plates, drifting on the Earth’s surface, dive into the Earth and form trenches. Seventeen reasons will be given why this is incorrect.
The flood began with a rupture of the Earth’s crust that raced around the globe in about 2 hours. For months, escaping subterranean water eroded the rupture to an average width of about 1,400 miles all along its 46,000-mile path—even on Earth’s Pacific side. The hydroplates were no longer prevented from moving at least a few hundred miles toward the Pacific side of the Earth.
Near the end of the flood, a “tipping point” was reached. So much mass had been removed from the Atlantic side of the Earth that the Mid-Atlantic Ridge started to buckle up. Hydroplates began sliding downhill on the remaining subterranean water, away from the rising Mid-Atlantic Ridge. This steadily removed gigantic amounts of weight from what would become the Atlantic floor, so the ridge and chamber floor rose even faster. Material within the Earth then had to shift toward the Atlantic side. Near the center of the Earth, where pressures are greatest and movement was most constricted, that shifting produced so much frictional heat that the inner Earth melted and shrank. (Magma is much more compressible than solid rock,2 as explained on pages 156-157.) Thus the center of the Earth began its transformation into what is today’s inner and outer core. Further shrinkage in the inner Earth caused the Pacific crust, surrounded by what is now called the Ring of Fire, to begin sinking. Portions of the Pacific crust directly opposite the center of the rising Atlantic floor buckled inward, forming trenches. In less than a day, the Pacific plate subsided at least 30 miles—enough to remove any obstacle to the hydroplates sliding away from the Mid-Atlantic Ridge.
Weeks later, the oceanic ridge that began rising in the Atlantic had extended to the Pacific side of Earth. After many years, gravity squeezed the Earth back toward its nearly spherical shape. Mass imbalances remain, so earthquakes now occur, and continents sporadically shift—not drift—toward the trench region of the Pacific.
Imagine standing at the edge of a vast depression that reminds you of the Grand Canyon, but this depression is several times deeper. Its smoother walls are almost as steep as the Grand Canyon’s, but the view across the 60-mile-wide depression is never obstructed by intermediate land forms. This “canyon,” thousands of miles longer than the Grand Canyon, does not have sharp turns. Such depressions, called ocean trenches, would be the leading natural wonders of the world if water did not hide them. (Average ocean depth is 2.5 miles; the deepest trench reaches 6.86 miles below sea level.) Why are sixteen trenches concentrated on the western Pacific floor?
Surprisingly, trenches contain shallow-water fossils.3
Materials [like fossils] which are usually supposed to be deposited only in shallow water have actually been found on the floor of some of the deep trenches.4
Why are such unlikely fossils in a remote part of the ocean—a thousand times deeper than one would expect?
Today, most of the Earth’s crust is vertically balanced, like blocks of ice floating in a pan of water. Less dense blocks “float” higher up than denser blocks. This is called isostatic equilibrium. However, ocean trenches are Earth’s most glaring departure from this equilibrium. This imbalance may be an important clue for how trenches formed. As various authorities have written:
... trenches are characterized by large negative gravity anomalies. That is, there appears to be a mass deficiency beneath the trenches, and thus something must be holding the trenches down or else they would rise in order to restore isostatic equilibrium.5
The most striking phenomenon associated with the trenches is a deficiency in gravity ... Measurements of gravity near trenches show pronounced departures from the expected values. These gravity anomalies are among the largest found on Earth. It is clear that isostatic equilibrium does not exist near the trenches. The trench-producing forces must be acting ... to pull the crust under the trenches downward! 6
In a modeling study [of the deepest ocean floor], the team reproduced the Challenger Deep’s topography and fissure pattern only after factoring in a massive and mysterious downward force tugging at the Pacific Plate.7
You now know what that mysterious force was. Simply put, trenches were pulled down, not pushed down. Today, the downward pull of gravity in and above trenches is less than expected even after adjusting for the trench’s shape and depth, so less mass exists under trenches than one would expect. It is as if something deep inside the Earth “sucked” downward the material directly below trenches. This would reduce the mass below trenches. (If you want to show a slight weight loss, weigh yourself while sailing over a trench.)
A useful illustration is to think of a slight vacuum, or reduced mass, under trenches—much like a partial vacuum, which “nature abhors.” That is, nature always tries to move material to fill a vacuum. If one waited long enough, material inside the Earth would flow in under trenches to fill this “partial vacuum.” Today, crustal plates move an inch or so each year toward trenches, so this “partial vacuum” is slowly being filled in modern times. Later, we will see where the missing mass under trenches went and what created the “partial vacuum.” Clearly, this “filling in” has not been going on for millions of years.
A technique called seismic tomography has shown that rock in the upper mantle is denser under continents than under oceans. The technique uses earthquake waves to “see” inside the Earth, just as a CAT scan uses x-rays from many angles to “see” inside your body. Each earthquake radiates waves through the Earth. Knowing the precise time of an earthquake and the times the waves reach seismometers around the world, scientists can calculate each wave’s average velocity along a specific path.
Figure 84: Spin. A spinning object, such as a figure skater or the Earth, spins faster if it becomes more compact about its spin axis. This skater starts a spin with outstretched arms. Then, as she pulls her arms in near her spin axis, she spins so fast she becomes a blur.
Gravity tries to make the Earth as compact and round as possible. Earthquakes cause the Earth to become more compact and spin slightly faster.8 Therefore, the further back in time we look, the less compact we should find the Earth, at least until we arrive at the time the out-of-balance condition arose. Because earthquakes can occur deep within the Earth, the out-of-balance condition affected the entire Earth and, as you will see, produced trenches and the Ring of Fire.
Earthquakes. The major goal of earthquake research is to predict earthquakes. Normally, the best way to predict something is to understand how it works. Because, earthquakes are poorly understood, much effort is spent studying events that sometimes seem to precede earthquakes—earthquakes precursors, such as strange animal behaviors, abrupt changes in water levels in wells, swelling of the ground, and sudden irregularities in local geyser eruptions.
Plate tectonic theory claims that earthquakes occur when plates rub against each other, temporarily lock, and then jerk loose. If so, why are some powerful earthquakes far from plate boundaries? 10 Why do many earthquakes occur when water is forced into the ground? 11 Following the 2004 Sumatran earthquake and tsunami that killed 230,000 people, why was there a permanent drop in the pull of gravity below the epicenter? According to plate tectonics, the mass should not have changed. This was measured very precisely by the GRACE satellite system.12
Figure 85: Hydroplate Explanation for Trenches. (A) Before the flood, the weight of rock and water, pushing down on the subterranean chamber floor, balanced the floor’s upward pressure. The rupture destroyed that equilibrium. Directly below the rupture, the imbalance grew as escaping, high-velocity water and the 60-mile-high, unsupportable, crumbling walls widened the globe-encircling rupture hundreds of miles. Eventually, the imbalance overwhelmed the strength of the floor. First, the Mid-Atlantic Ridge buckled, or sprang, upward. Then, as Europe, Africa, and Asia slid eastward and the Americas plate slid westward (based on today’s directions), weight was removed from the rising floor, so it rose faster, accelerating the hydroplates even more. Pressure directly under the floor, represented by the large black arrows, naturally decreased as the floor rose.
(B) During the flood phase, the escaping subterranean water eroded and thinned the preflood crust to a thickness of about 30 miles. Frictional heating from movements near the center of the Earth began melting solid rock which then contracted, because of the extreme pressure and magma’s great compressibility, contracted, as explained in “Magma Production and Movement” on pages 156–157. This caused the crust on the Pacific side of the Earth (the Pacific plate ) to subside by at least 30 miles, fracturing the Pacific plate at thousands of places within the boundaries of the Ring of Fire! 13 That drop steepened the downhill slope of the sliding hydroplates, allowing them to slide into the Pacific region without major obstructions. Downward buckling and deep faulting formed trenches. All this melting lubricated the shifts inside the Earth and allowed gravitational settling, which released much more heat, increased Earth’s spin rate, and converted the inner Earth to today’s inner and outer core—monumental changes. The thick layer of magma expelled up onto the top of the sunken Pacific plate provided most of the heat that drove the ice age and accounts for the almost 40,000 volcanoes on the Pacific floor. Even today, magma sometimes breaks out and escapes upward, heating part of the ocean and creating “El Niņo” weather conditions.14
A fault is a fracture in the Earth’s crust along which movement has occurred. During most earthquakes, opposite sides of a preexisting fault “unlock” and suddenly slip. If the side of a fault nearest a distant seismometer moves toward the seismometer, a compression wave will be detected first. If that side moves away from the seismometer, a tension wave will be detected first. By examining the first wave to reach many seismometers, one can deduce the orientation of the fault plane and whether the earthquake was triggered by compression or tension. Earthquakes near a trench are almost always due to horizontal tension perpendicular to the trench axis—not compression as predicted by plate tectonics.15 Measurements also show that micro-earthquakes on the ocean floor tend to occur at low tide.16
But some earthquakes are “slow”—very slow. Every year or so, slow-slip occurs along some faults, moving the ground horizontally inches per week, rather than feet per second, as in a normal earthquake. Slow-slip is often accompanied by tremors, detectable only on seismometers. Sometimes this slow-slip mysteriously reverses direction! 17
Shallow earthquakes sometimes displace the ground horizontally along a fault, as occurred along the San Andreas Fault during the great San Francisco earthquake of 1906. Western California slid northward relative to the rest of North America. The San Andreas Fault has several prominent bends, so just as two interlocking pieces of a jigsaw puzzle cannot slip very far relative to each other, neither can both sides of the curved San Andreas Fault. Furthermore, if slippage has occurred along the San Andreas Fault for eons, friction should have greatly heated the sliding surfaces. Drilling into the fault has not detected that heat.18 Evidently, little movement has occurred over millions of years or the walls of the fault were lubricated.
Maybe both.
Almost 90% of all earthquake energy is released under trenches. Earthquakes often occur near planes, called Benioff zones, that slope downward from trenches at 30°–60° angles below the horizontal. These earthquake zones extend to depths of about 410 miles.
A prominent feature on all ocean floors is the Mid-Oceanic Ridge. One characteristic of the ridge figures prominently in two competing theories for how trenches formed. As explained in the preceding chapter, the ridge is cracked in a strange pattern. Some cracks are nearly perpendicular to the ridge axis, while other cracks are parallel to it. Their shapes and orientation are best explained by the stretching of the ridge.26 What would stretch the ridge in two perpendicular directions? These cracks are easily seen along the Mid-Oceanic Ridge in Figure 44 on page 112.
More than 40,000 submarine volcanoes, called seamounts, litter the Pacific floor. Some rise higher above the seafloor than Mount Everest rises above sea level. Strangely, the Atlantic has few seamounts. If, as the plate tectonic theory claims, one plate dives (subducts) beneath another, why aren’t seamounts and soft sediments scraped off the top of the descending plate?
About 2,000 flat-topped seamounts, called tablemounts, have tops that are 3,000 – 6,000 feet below sea level. Evidently, as these volcanoes tried to grow above sea level, wave action planed off their tops. Either sea level was once 3,000 – 6,000 feet lower, or ocean floors were 3,000 – 6,000 feet higher, or some combination of both. Each possibility raises new and difficult questions.
More than half of the world’s active and dormant land volcanoes and 90% of the world’s earthquakes occur along the Ring of Fire, shown in the inset map on page 152. Obviously, that 25,000-mile-long, horseshoe-shaped path is a region that was violently disturbed in the past.
From deep in the mantle, enormous amounts of melted basalt, called flood basalts, rapidly 27 spilled upward onto the Earth’s crust—especially onto the Pacific Basin. Above sea level, some “spills” that we can examine today are large enough to cover the eastern United States to the height of the Appalachian Mountains—from Atlanta to New York City and from the Appalachian Mountains to the Atlantic Ocean. More than a dozen of these convulsions have occurred at different places on land, dwarfing in volume the total magma in all volcanic cones. The volume of all “spills” below sea level may be a hundred times greater.
Rocks are composed of various minerals, some containing molecules of water. These minerals are not wet to the touch, because each water molecule is locked separately in a mineral’s crystalline structure, and the water occupies only about one-thousandth of the rock’s volume. However, the inner Earth is so large that it probably contains several oceans’ worth of water. Some heating process may have released that water, allowing it to collect in larger pockets. That would account for pooled water (with a total volume equal to the water in the Arctic Ocean) that is dispersed 500–750 miles under eastern Asia and part of western North America.28
Figure 88: Trench Cross Section Based on Hydroplate Theory. Notice that the trench axis will generally not be a straight line. Sediments (green) hide the top of a fault plane that would otherwise rise a few hundred feet above the floor. Other sediments (not shown) and flood basalts (dark gray) cover most of the western Pacific floor. The three large black arrows show the direction of the rising Atlantic and the forces that downwarped the mantle and the Pacific plate. Earthquakes occur on the many faults produced, especially in Benioff zones and at low tides. Most volcanoes are not above Benioff zones, but are near a myriad of other faults near the center of the western Pacific, where there was considerable downwarping and shearing.