Buzz
Earth trembles every 26 seconds, a peculiar phenomenon that scientists cannot trace back to its origin. What's even more puzzling is that this rhythmic shaking began precisely on June 6, 1961.
On June 6, 1961, geologist Oliver stumbled upon this periodic tremor for the first time. He speculated it stemmed from the Earth's crust in the expanse of the Atlantic Ocean, with stronger tremors anticipated in the Southern Hemisphere during winter.
However, contemporary scientists argue that this regular tremor, which was once believed to emanate from the Atlantic Ocean, has been localized beneath the surface of the Gulf of Guinea in West Africa.
The term 'microseism,' also known as 'microseismicity,' was first coined in the early 1960s by researcher Jack Oliver while stationed at the Lamont-Doherty Geological Observatory. He proposed that the pulses originate from the 'Southern or equatorial region of the Atlantic Ocean,' with heightened activity during the summer months in the Northern Hemisphere (corresponding to winter months in the Southern Hemisphere).
Current theories posit that earthquakes are essentially the result of energy release from the Earth's crust, giving rise to seismic waves. However, numerous factors contribute to small earthquakes, extending beyond crustal movements, volcanic eruptions, nuclear tests, and even human activities, albeit these earthquakes are irregular. This marks the first encounter for scientists with Earth's 26-second tremor phenomenon.
The Enigma of Earth's Tremors: Unraveling the Mystery
Garrett Uler, a scientist at the University of Washington, believes that the Gulf of Guinea, being near the equator and affected by the Sun more intensely than other places, experiences frequent collisions between equatorial currents and the shores, resulting in tiny earthquakes. This scenario is akin to lightly tapping on one end of a table, causing the other end to vibrate.
However, not everyone agrees with this explanation. A group of Chinese scientists contends that the source of the 26-second seismic cycle is not waves hitting the continental shelf but rather volcanic activity. There is a volcano on an island near the Gulf of Guinea, and Japan's Mount Aso has also triggered minor earthquakes.
However, both explanations fail to address a fundamental issue: if the microseismic earthquakes are caused by ocean waves or volcanic activity, then why doesn't this occur elsewhere on Earth? Why are there earthquakes beneath the ground in the Gulf of Guinea?
Earth has many regions near the equator like the Gulf of Guinea, and there are also numerous areas near volcanoes. So, why do such regular earthquakes occur only here?
Therefore, to this day, the super-small earthquakes with a 26-second cycle beneath the ground in the Gulf of Guinea remain an unsolved mystery, with gaps in explanations about the Sun's heat causing waves to crash onto the coast or explanations about nearby volcanoes. Thus, even in the 21st century, Earth still holds many mysteries for humanity.
More than half a century after scientists first heard the strange beat, the answer remains elusive. Many scientists believe there are still aspects worth exploring in seismology, such as mapping Earth's geology, while the peculiar beat 'has no significance for understanding the structure of the Earth.'
In fact, in the realm of science, there has long been a saying that 'humans know more about the universe than Earth' because to travel to space, humans only need to reach escape velocity (with Earth's escape velocity approximately 7.9 km/s), but to explore inside the Earth requires drilling deep into the ground. To this day, the deepest hole drilled by humans barely reached a depth of less than 13 km and hasn't even penetrated the crust, let alone the mantle and core.
This phenomenon occurs because the temperature inside Earth is too high, the rock layers are too hard; when the drill bit reaches a depth of 10,000 meters, the gravitational force of the Earth itself overwhelms the drill bit, making drilling deeper into Earth akin to using a noodle to poke through a rock.
And if you think about drilling from the ocean floor, it's even more impossible because the deepest part of the Mariana Trench is still less than 12 km deep, while the average thickness of Earth's crust is up to 37 km. Therefore, drilling from the ocean floor under the high pressure of seawater is very difficult and fraught with unpredictable dangers.
Therefore, in the near future, until there is a major breakthrough in material technology, humans truly cannot explore the interior of Earth, and the unanswered questions inside Earth will remain in a mysterious state for a long time.
