Earthquakes are feared since ancient times. Even more so than volcanoes, as you can never tell when or where an earthquake might strike. Apart from the damage it causes, there are more interesting things we can learn about earthquakes. Here we bring you some earthquake facts you may not know about!
Earthquakes have their positive sides too. Did you know that earthquakes presses land further up? Loosening and churning soil, enabling nutrients and minerals to be transferred evenly, are events that result in a very fertile type of soil. Earthquakes also help vegetation to flourish.
Earthquakes also allow scientists to learn more about the structure of the Earth by seeing how seismic waves behave. One common technique for finding oil has been to explode certain places before studying the seismic results. With earthquakes, you don’t need explosives. The Earth opens up on its own. Isn’t that amazing?
Not all earthquakes are deadly. In fact, millions of earthquakes occur each year, and most of them are too weak to be recorded. According to the NEIC or the National Earthquake Information Center, only 100 or so out of the total number of earthquakes that happen each year are capable of causing real damage. Learn more about this amazing geophysical phenomenon with these 40 earthquake facts.
- The shaking of the ground in an earthquake only makes up 10% of its energy.
- The remaining 90% of an earthquake’s energy creates underground fractures or heats up the Earth’s interior.
- Ground ruptures caused by earthquakes can measure up to 1,000 kilometers long.
- An estimated 500,000 earthquakes take place around the world every single year.
- Humans feel only an estimated 100,000 earthquakes out of the yearly total.
- The Greek scientist and philosopher Thales of Miletus made the first speculations about earthquakes in 585 BC.
- Aristotle also made speculations about earthquakes in 340 BC.
- In 132 AD, Chinese polymathic scientist Zhang Heng invented the first seismometers in Han Dynasty China.
- The modern science of seismology began in 18th Century Europe.
- Robert Mallet made the first seismological experiments using explosives in 1857.
- He also became the first man to ever use the word seismology.
- In 1897, Emil Wiechert discovered that the density of the Earth is greater than the density of a rock.
- Richard Oldman discovered that the Earth does have a core.
- Harry Reid developed the elastic rebound theory of earthquake mechanics back in 1910.
- Harold Jeffreys used earthquakes to discover the Earth’s liquid outer core in 1926.
- Scientists completed modern plate tectonics theory in the 1960s.
- A related field to seismology is paleoseismology, which studies earthquakes from past geological time periods.
- The Roman Pliny the Elder once described earthquakes as underground thunderstorms.
- The Greek God Poseidon also ruled over earthquakes as well as the sea.
- 90% of the world’s earthquakes take place along the Pacific Rim of Fire.
- 81% of the world’s most powerful earthquakes take place along the Pacific Rim of Fire.
Shaking and ground ruptures are the most common effects of an earthquake.
Just how powerful the shaking becomes depends on the quake’s magnitude, as well as the distance from the epicenter. Other factors include the local geography and geology, increasing or decreasing the quake’s power.
Ruptures, though, tend to follow the fault along which a quake takes place, usually breaking the ground for several meters at least. Ground ruptures can prove devastating to roads, bridges, houses, and even dams and nuclear power plants.
Liquefaction can also happen during an earthquake.
Liquefaction occurs when a building stands on loose soil or ground that has plenty of groundwater. Reclaimed land near the sea or other bodies of water can also cause liquefaction to happen. When an earthquake strikes, the shaking separates the solids in the ground away from each other.
Water then fills up the spaces between them, turning the ground into a slurry, which cannot support a building. Buildings literally sink into the ground as a result. This phenomenon had led many countries to require buildings to stand on solid-rock foundations.
Earthquakes can also cause fire and landslides.
The shaking caused by an earthquake can damage electrical lines, which can electrocute people and start fires. Flammable materials that can start fire caused by loose electrical lines include curtains, carpets, upholstery, clothing, and paper.
Leaking gas lines prove especially volatile, too. Large concentrations of leaking gas can even outright explode. Apart from the devastating power of fire, earthquakes could also destabilize hillsides and mountainsides. This results in landslides, where large parts or the slope itself literally falls down.
Due to a landslide’s ability to bury entire communities, governments and private organizations warn people to stay away from steep and sloping areas.
Tsunami is one of the deadliest effects of an earthquake.
Tsunamis happen when a powerful earthquake occurs underwater. This type of earthquake causes large volumes of water to move quickly, similar to how jolting a bathtub causes the water inside to slosh around. In deep water, the movements of the waves don’t become apparent, with cases existing of men at sea not noticing tsunamis moving under them. They only realize the results when they find the devastated shores. Tsunamis can also travel very far, with earthquakes off the coast of the Americas able to damage countries as far away as Japan.
The 1556 Shaanxi Earthquake remains the deadliest in human history.
Chinese records estimate the number of deaths at 830,000 spread out over an area 840 km wide. In addition to Shaanxi Province, nine other provinces also suffered from the earthquake: Anhui, Gansu, Hebei, Henan, Hubei, Hunan, Jiangsu, Shandong, and Shanxi.
In Shaanxi Province alone, the cities of Huayin and Weinan saw complete destruction. And in some places, ruptures opened up as deep as 20 meters, with landslides occurring widely. Even cities as far away as Chengdu, Beijing, and Shanghai saw damage resulting from the earthquake. Its colossal effects led to Chinese historians calling it the Jiajing Great Earthquake after the reigning Emperor of the Ming Dynasty at the time.
The 1976 Tangshan Earthquake has the distinction of being the deadliest earthquake of the 20th century.
The momentous earthquake killed 242,000 people and destroyed an estimated 85% of the buildings in the city of Tangshan. It also caused widespread flooding in Tangshan’s coal mines, with the city’s coal industry needing a full year to recover. The earthquake also damaged the railways linking Tangshan to the rest of China, in particular the cities of Beijing and Tianjin. This made it even more difficult for help to reach the city after the disaster.
The 1960 Chilean Earthquake remains the most powerful earthquake ever recorded.
Taking place on May 22, 1960, the earthquake reached a magnitude of 9.5. In comparison, the 2004 Indian Ocean earthquake only reached a magnitude of 9.3. The earthquake also caused a series of tsunamis, which affected not just the Chilean coast, but also Hawaii, New Zealand, New Guinea, the Philippines, and Japan. An estimated 6,000 people died from the quake and tsunamis both, and caused damages worth up to $800 million.
Aftershocks tend to follow earthquakes.
Talk about worrying examples of Earthquake Facts. Aftershocks result from the ground adjusting to the geological changes courtesy of the preceding quake. The danger comes from how unpredictable aftershocks are, with no way to tell how many of them will occur, when they will strike, and how powerful they can be.
Foreshocks sometimes happen before an earthquake
Scientists estimate that foreshocks occur in 40% of earthquakes with magnitudes of less than 7, and in 70% of earthquakes with magnitudes greater than 7. However, since not all quakes have foreshocks, scientists don’t consider foreshocks reliable in predicting when and how powerful an earthquake will strike. The 2004 Indian Ocean earthquake, for example, did not have foreshocks preceding it.
Volcanoes also cause earthquakes of their own.
The magma moving up from under the Earth to the surface causes the surrounding ground to shake. The extreme heat of the magma also exists as a factor, as the geography changes in response to the heat. Even without an eruption, volcanic earthquakes can still take place, as magma moving around underground still affects the surrounding rock. Volcanologists monitor those quakes, as any changes in their number and magnitude could serve as a warning for a volcanic eruption.
Human activity caused the 2011 Oklahoma Earthquake.
A strange, but true example of earthquake facts. Specifically, wastewater produced by the oil industry injected into underground storage wells caused a fracture in the Wilzetta fault. The fracture resulted in a magnitude 5.5 quake, with a preceding magnitude 4 foreshock. Thankfully, there are no fatalities but only injuries suffered by two people. Fourteen homes in Prague, Oklahoma, however, were severely damaged, as did St. Gregory’s University in Shawnee.
Seismometers and seismographs make up the primary seismological tools.
Seismometers measure the vibrations in the Earth and then transmit them to seismologists for study. They don’t usually record them, but when they do, they’re called seismographs instead of seismometers. In both cases, though, seismologists bury them underground, which serves to protect them from surface vibrations that can compromise data.
Some animals have the ability to detect earthquakes.
While animals are the first creatures to feel an earthquake, statistics and scientific studies show that they can’t predict them as early as weeks or months. The animals pick up the vibrations in the Earth that humans lack the sensitivity to pick up and react on instinct. Another strange, but true example of earthquake facts.
Seismologists generally struggle to predict when an earthquake will happen.
Many scientists have tried hard since the 1970s, but all methods always end up in failure. This has led some seismologists to argue the impossibility of predicting earthquakes. Others disagree, and instead argue that the current understanding of earthquakes just remains incomplete.
Some buildings use weights to limit an earthquake’s possible damage.
Tall and lightweight buildings feature mobile weights resting on springs that adjust as the building sways. This keeps the building stable not just against the shaking from a quake, but also from the wind. In particular, they balance the stresses from excessive movements and keep them from becoming too much.
Other buildings use slosh tanks to protect themselves from an earthquake.
Usually filled with water, slosh tanks usually stay near or on a building’s roof, with the movements of the liquid inside balancing any swaying caused by a quake. That said, they require large amounts of liquid to stay effective, usually around 5% of the building’s total weight. If water makes up the liquid in the tank, they also double as an emergency reserve, when disasters such as fire strikes.
Other buildings simply reinforce their structures to protect themselves from an earthquake.
The most common reinforcement against earthquakes involves adding steel frames along the outside of a building’s lower floors. Alternatively, reinforcement can take the form of encasing the building’s lower floors with additional walls made from reinforced concrete.
Other reinforcements include rigidly binding neighboring buildings together, to keep any one of them from falling on the others and starting a domino effect.
The US Federal Emergency Management Agency (FEMA) encourages citizens to do their part to prepare for an earthquake.
Earthquake preparations include stockpiling emergency food and water reserves, as well as medicine. The last becomes especially important for people with specific prescription medicines, as getting them may prove difficult after a quake.
FEMA also encourages citizens to also have emergency power sources if possible, much like the case with hospitals and other critical services. Citizens should also inform themselves about shutting off their homes’ gas supplies to minimize gas leaks and their impending dangers.
Earthquakes also take place on the Moon.
Both the Apollo and unmanned missions to the Moon have detected and recorded hundreds of quakes on the Moon. They typically have magnitudes of less than 5.5, with scientists thinking them caused by tidal stresses caused by the interactions between the Earth and the Moon’s gravity. Scientists have also used them to learn more about the inner layers of the Moon. A moonquake might sound like a delicious dessert, but it’s not exactly a sweet phenomenon outside the Earth. Talk about astronomical examples of earthquake facts.
Mars once had Marsquakes of its own.
Evidence such as magnetic striping over Mars’ southern hemisphere proves that Marsquakes are possible. On Earth, such phenomena result from the splitting and spreading of thin crust, but on Mars, it remains unclear if the case remains the same. At the very least, Mars once had active volcanoes, with the biggest of them all, Olympus Mons, easily as big as France. Today, though, Mars appears dead tectonically, and scientists think that if Marsquakes do still happen, they only happen once every million years.