Seamapping and Earthquaking

A few acronym organisations have bundled together with the aim to map the sea floor, in its entirety, by 2030. Currently, just over a quarter of the sea floor is mapped in high resolution. Already, the benefits of initiatives like this are being proven, with discoveries all the time. For example, early in 2024, the Schmidt Ocean Institute discovered four underwater mountains, previously unknown, as they sailed from Costa Rica to Chile. Last year, the same crew discovered a 1,600 metre underwater mountain off the coast of Guatemala. 

According to the National Oceanic and Atmospheric Administration, there could be more than 100,000 seamounts taller than 1,000 metres high. All of these underwater discoveries are tracked in a bathymetric database, which is a store of map and geographical data which represents the topography of ocean floors. Fortunately, it’s not an Oracle database, so it works. 

Mapping the seafloor is simply another aspect of exploring the ocean, and ocean exploration is at the heart of human exploration. We grew up on the lore of Christopher Columbus, who, in 1492, embarked on his first voyage from Spain and reached the Americas, landing on an island in the Bahamas on October 12. I’m not sure there are many better places to land.

Seafloor mapping, along with all other human exploration, is unequivocally a good thing. In particular, ocean floor mapping benefits the world by providing better navigation for ships and helping us understand geological processes so we can move towards predicting and mitigating the impact of natural disasters, like earthquakes and tsunamis. It also allows us to utilise the sea's resources (minerals) in a way which doesn’t completely bugger up the natural ecosystem, and it helps scientific research through the understanding of substrates.

Hopefully, further down the line, it should also help grow the ocean tourist industry and further underwater infrastructure development when we lay more fibre optic submarine cables and perhaps transport for more underwater rail and road links. I don’t want to go all James Bond villain on you, but 71% of the earth’s surface is water, and we underutilise it. But with autonomous ships now a reality, mapping has never been easier.

Earlier I spoke about predicting natural disasters and I want to focus the rest of this article on the potential benefit of doing just that. In The Signal and the Noise* Nate Silver explains why it’s hard to predict earthquakes.

The phenomenon between earthquake magnitude and frequency is well understood and is known as the Gutenberg-Richter law. This states that earthquake magnitudes are distributed exponentially as LogN(m) = a − bm, where N(m) is the number of earthquakes with magnitude larger or equal to m, b is a scaling parameter, and a is a constant.

In really simple terms, smaller magnitude earthquakes occur much more frequently than larger ones. In slightly less simple terms, the relationship between earthquake magnitude and frequency is a power law, which means that for a one point increase in magnitude on the Richter scale, an earthquake is about ten times less frequent. That means when you plot frequency on a log scale, with magnitude on the other scale (which itself is a logarithmic scale), you get a straight line.

However, knowing the frequency of earthquakes tells us nothing about forecasting when an earthquake will hit. Sometimes, there are large foreshocks, such a 7.5 magnitude earthquake in Japan on March 9th 2011. This may mean nothing. But, just 50 hours later, the 9.1 magnitude Tōhoku earthquake, which you probably have heard of, struck 45 miles off the coast of Japan. This powerful earthquake (the 4th most powerful ever recorded) led to a tsunami, at some points nearly 40 metres high (Miyako City), the deaths of nearly 20,000 people, a nuclear powerplant reactor meltdown, an economic cost of $300 billion and about 0.5% decrease in Japanese real GDP growth.

Between the earthquake and the tsunami hitting land, Japanese residents had less than a thirty minute warning. If we knew with some probability, that the 7.5 magnitude foreshock would lead to an even larger earthquake just 50 hours later, we could have prevented deaths. But it’s not easy. At the moment, that capability does not exist. For every genuine foreshock of an earthquake, there is a lot of noise. Only 50% of major earthquakes are preceded by a foreshock. Even then, small foreshocks are not always reported, especially in regions of the world where seismology equipment is not sensitive, or modern enough. 

One country that does have sensitive seismology and earthquake monitoring systems is Taiwan. This is borne out of necessity due to its position in the Pacific Ring of Fire, an area of high seismologic activity (about 90% of the world’s earthquakes occur in the Pacific Ring of Fire).

Taiwan enhanced it’s earthquake monitoring and early warning network after the devastating 1999 Jiji (Chi-Chi) Earthquake (also known as 9-21 earthquake), which killed 2,400 people. Taiwan now has 119 ground monitoring, 9 ocean bottom seismometers and 350 real time strong stations, in what is called the Central Weather Bureau Seismographic Network.

In addition, Taiwan has developed early warning systems to provide rapid alerts which can issue warnings within 20 seconds after a large earthquake in east Taiwan, or 10 seconds in the Taipei urban area or, in some cases, 2 - 8 seconds warning when the sensors are close to the epicentre.

Enhanced mapping and exploration of the seafloor and implementing technology such as Ocean Bottom Seismometers and shallow buoys with GPS (which have been seen to detect movements as small as 1 - 2 cm), provide a future where earthquakes are predictable.

Taiwan, along with Japan, are probably two of the best examples of where technology has helped humans overcome the perils of natural disasters. Taipei 101, the 11th tallest building in the world, at 508m high, sits 200 metres away from a major fault line. One of the earthquake damage prevention technologies used is a tuned mass damper, which is a 660-ton sphere between the 88th and 92nd floors. The dampener itself can move five feet in any direction. 

Taiwan is an example of where technology can help us overcome nature and ocean exploration provides another opportunity for us to do this. Knowing more about our world helps us. When you think about it, it’s pretty crazy that we have mapped most of the landmass of the world but very little of the ocean. Once we’ve mapped it, the opportunities will be endless.

Taiwan and Japan are evidence that countries that are more advanced, developed, and wealthy have the technology to reduce deaths occurring from natural disasters compared to countries that are less advanced, underdeveloped, and poor. When it comes to natural disasters, economic development saves lives. The 9.1 magnitude 2011 Tōhoku earthquake was devastating and killed 20,000 people. The 9.1 - 9.3 magnitude 2004 Indian Ocean earthquake and tsunami (Boxing Day tsunami), the third most powerful earthquake ever recorded, killed 225,000, and the 2010 Haiti earthquake killed somewhere between 100,000 - 300,000** (the seventh deadliest earthquake). Not all of the difference can be attributed to the level of technology deployment and economic development - there will always be geographical factors - but a significant proportion can be.

*I strongly recommend reading the entirety of The Signal and the Noise. And then, reading it again, it’s an excellent book.

**a useful barometer of the development of a country is how accurate and precise death, injuries and cost figures are after a natural disaster.