© Getty Images

The Indian Ocean earthquake -

The magnitude of the devasting 2004 Indian Ocean earthquake measured between 9.1 and 9.3 on the Richter scale, making it the third-most powerful quake since 1900.

© Getty Images

A ground-breaking event -

The earthquake and subsequent tsunami claimed the lives of over 230,000 people. The natural disaster was, quite literally, a groundbreaking event, the force of the quake altering the contours of the Earth.

© Getty Images

Knocking out the North Pole -

It did this by modifying the shape of Earth in a number of minute yet significant ways, NASA scientists subsequently determined. Most notably, the December 26 earthquake actually moved the North Pole 2.5 cm (1 in) in an eastward shift.

© Getty Images

The town that moved -

Besides its ability to shift landmass, an earthquake can also move entire communities. In 2010, an earthquake measuring 8.8 struck the town of Concepción in Chile. The quake's violent force actually moved the town 3 m (10 ft) west from its original position, reported CNN.

© Getty Images

The 1960 Valdivia earthquake -

Astonishingly, Chile had seen worse. At 9.5 on the Richter scale, the 1960 Valdivia earthquake and tsunami, also referred to as the Great Chilean Earthquake, was almost off the scale. In fact, it's currently the most powerful quake ever recorded.

© Getty Images

Global implications -

Valdivia's seismic clout was such that shockwaves were felt in regions on the other side of the world, and reverberated for days. The resulting tsunami, meanwhile, washed up in destinations as far away as Japan and the Philippines.

© Getty Images

Deadliest earthquake in recorded history -

History's deadliest earthquake in terms of casualty numbers is that which struck Huaxian in China's Shaanxi province in 1556. Emperor Jiajing (pictured), 12th ruler of the Ming dynasty, presided over a tragedy that claimed an estimated 830,000 lives.

© Getty Images

New Madrid Earthquakes -

From December 1811 through March of 1812, there were over 2,000 earthquakes in the central US Midwest. This catastrophic phenomenon, known as the New Madrid Earthquakes, destroyed towns, created a huge lake, and even reversed the flow of the Mississippi River!

© Getty Images

What is the Ring of Fire? -

The aptly named Ring of Fire is a string of active volcanoes and frequent earthquakes set around the edges of the Pacific Ocean. Its outline includes the Pacific coasts of South America, North America, Russia's Kamchatka Peninsula, Japan, and several islands in the western Pacific Ocean.

© Shutterstock

The Tōhoku earthquake and tsunami -

Measuring a striking 9.0–9.1, the 2011 Tōhoku earthquake and tsunami was the biggest earthquake in Japan's recorded history and the fourth biggest quake in the recorded history of the planet.

© Getty Images

Enough power to shift the Earth's axis -

According to NASA, the March 11, 2011, earthquake may have shortened the length of each Earth day and shifted its axis. As a result of the quake, the Earth span almost two microseconds faster, the adverse effect being the shortening of the day, also by two microseconds. 

© Getty Images

Weather or not -

Weather plays no part in the creation of an earthquake. While altitude, temperature, and humidity can effect atmospheric pressure, the US Geological Survey notes that the only correlation between earthquakes and weather is that significant changes in atmospheric pressure caused by major storms such as hurricanes have been shown to occasionally trigger what are known as "slow earthquakes." These do not result in the ground shaking associated with traditional earthquakes.

© Shutterstock

Man-made causes -

Drilling for oil and gas can induce mini-earthquakes, though damage is minimal, cracking walls perhaps, or toppling bricks. But seismologists have issued warnings that regular shaking caused by tremors, no matter how small, can dramatically increase the chances of bigger, more dangerous quakes.

© Getty Images

The effect of the Sun -

According to ScienceAlert, researchers in the US have discovered a link between the position of the Sun and Moon and small tremors deep within the San Andreas Fault.

© Getty Images

The effect of the Moon -

The findings suggest that the gravitational pull of the astronomical bodies could be causing the Earth's plates to move up and down like the ocean's tides. Seismologists, though, are quick to point out that the gravitational pull of the Sun and Moon is far too weak to trigger an earthquake on its own.

© Getty Images

The first seismographs -

The earliest instrument to resemble a seismograph—a "seismoscope"—was invented by the Chinese mathematician and philosopher Chang Heng in 132 CE. His device, however, didn't record the strength of earthquakes; it only indicated that an earthquake was occurring.

© Shutterstock

Vital recording device -

The first seismograph was developed in 1890. Today there are more than 150,000 earthquakes per year strong enough to be felt by people and 900,000 recorded by seismographs.

© Getty Images

Japan is on a seismic hit list -

Of these, Japan experiences around 1,500 earthquakes every year. Pictured are the ruins of Tokyo's Nihonbashi district after the Great Kantō Earthquake of 1923. More than 110,000 souls perished in the calamity.

© Getty Images

City to city -

And, of course, San Francisco is no stranger to earthquakes: in 1906 a magnitude 3.1 quake flattened the city. By the way, did you know that San Francisco is edging towards Los Angeles at a rate of 5 cm (1.96 in) per year? This is because the city perches on the edge of the North American Plate, which is slowly moving southward.

© Shutterstock

High-risk destination -

According to the World Risk Report 2022, the Philippines has the highest overall disaster risk, meaning it's the country most vulnerable to extreme natural events such as earthquakes, tsunamis, floods, and drought. India and Indonesia rank second the third, respectively.

© Shutterstock

Low-risk destination -

If you're looking for a country at the least risk of experiencing a natural disaster, head for the Gulf state of Qatar.

© Shutterstock

The economic damage -

Earthquakes often cause billions of dollars-worth of damage. Given the country's long history of earthquake disasters, Chile announced in early 2023 the signing of a deal with the World Bank for insurance against high-intensity earthquakes that would impact the country's fiscal policy and public debt.

© Getty Images

On alert -

Costa Rica is one of the countries that borders the Ring of Fire. The nation is on near-permanent high alert, meaning there is more than a 20% chance of a potentially-damaging earthquake within the next 50 years. Fueling the prospect is the Cordillera mountain range, formed by a string of volcanoes—many of them still active.

© Getty Images

A golden opportunity -

Here's an interesting fact: more than 80% of the world's gold deposits were formed due to ground-rattling earthquakes. This is because gold seams tend to form when mineral-rich water flows through networks of cracks in rocks deep below the ground.

© Getty Images

The world's top tsunami destination -

Unsurprisingly, the area of the world pounded most by tsunamis is the Pacific Ocean region.

© Getty Images

Measuring the speed of a tsunami -

In the absence of scientific instruments, a simple model for calculating tsunami speed flow is to examine field evidence, things like broken branches, water marks, debris caught in branches, and sediment deposited on floors of buildings. In other words, tsunami flow speed is calculated by matching the sediment suspended by the tsunami with the thickness and grain size distribution of the tsunami deposit, the detritus left in its wake.

© Getty Images

The power of erosion -

How tsunami waves behave—how far and fast they travel—is influenced by the ridges and valleys of the ocean floor and of our coastlines. And tsunami activity can actually erode the seabed to a point where in some places it has sunk to more than 20 m (65 ft).

© Shutterstock

The environment takes a hit -

Earthquakes and tsunamis can have a devastating effect on the ecosystem. Katchal, one of the Nicobar Islands in the Indian Ocean, felt the brunt of the 2004 tsunami. Huge swathes of coastal vegetation died after being enveloped by salt water. And as one of the worst affected islands, it lost some 90% of its population.

© Getty Images

Illustrating the fact -

Historically, the tsunami that swamped Lisbon after the earthquake on November 1, 1755, was one of the first to be recorded as a visual interpretation. Estimates place the death toll in the Portuguese capital on that day at around 12,000, making it one of the largest earthquakes in history.

© Getty Images

What does a mega-tsunami look like? -

Rarely is the world witness to a mega-tsunami. But on July 9, 1958, a strike-slip earthquake rocked Lituya Bay in Alaska, triggering a rockslide. The sudden displacement of such a  gargantuan amount of water created a tsunami of such immense height and power that it washed out trees to a maximum elevation of 524 m (1,719 feet) at the entrance of Gilbert Inlet.

© Public Domain

Taller than the Empire State Building -

To put that figure into staggering perspective, the tidal wave reached a run height taller than the Empire State Building as it raced towards shore. No wonder the effect of the Lituya Bay tsunami can still be seen today.

© Shutterstock

Destruction of our own doing -

And tsunamis, indeed earthquakes, can also be man-made. For example, the detonation of a nuclear device such as the one tested over Bikini Atoll in 1946 can mimic the devastation caused by either, though many times more profound and longer lasting.

Sources: (CNN) (Geology Science) (United States Geological Survey) (CNBC) (Los Angeles Almanac) (Reuters) (Smithsonian) (The Week) (National Oceanic and Atmospheric Administration)

See also: How long do you have to escape a tsunami?

© Getty Images