Katsuko Saruhashi, marine geochemist who measured CO2 in the oceans and showed how radioactivity spread from nuclear testing

Katsuko Saruhashi, linocut print, 9.25" x 12.5" by Ele Willoughby, 2025

This is my hand-carved and hand printed linocut portrait of Japanese geochemist Katsuko Saruhashi (1920-2007) who created tools that allowed her to make the first measurements of CO2 in seawater, raised the alarm about nuclear fallout, tracing it in the oceans, and researched peaceful uses of nuclear power. A supporter of women in science, she established the Society of Japanese Women Scientists and the Saruhashi Prize for Japanese women researchers for excellence in science and mentoring women scientists. Each print is 9.25” x 12.5” on Japanese kozo, or mulberry paper. I made this print for the #printerSolstice2425 prompt carbon.

Born in 1920, the story goes that her interest was sparked in science watching raindrops in primary school, wondering about the source of rain. Her parents believed in education, but she had to make a case to leave a secure insurance job at 21 to study chemistry. Her family witnessed how women struggled to support themselves without husbands or fathers in wartime. So her mother thought science might be a good way to ensure financial independence. She studied chemistry at the Imperial Women's College of Science (now Toho University). After completing her undergrad degree in 1943 she worked at the Geochemical Laboratory at the Meteorological Research Institute (now the Japan Meteorological Agency) with her mentor, marine chemist and lab director Miyake Yasuo, who had a strict policy against gender discrimination. She developed the first tool to measure CO2 in the oceans using pH and chlorinity, called Saruhashi's Table. She enrolled in the PhD program at the renowned University of Tokyo in 1957, where she was the first woman to earn a science doctorate. Her dissertation was on "The Behaviour of Carbonic Matter in Natural Water". With Miyake, she showed that oxidation of organic material increased CO2 in the ocean; prior to this, oceanic CO2 levels were attributed to dissolved calcium carbonate (for instance from in sea shells) and that global warming could be mitigated by seawater's supposed ability to absorb CO2. She not only showed this was untenable, she found the Pacific Ocean emits more CO2 than it absorbs! This has dire consequences for climate change. 

With Teruko Kanzawa from 1973 to 1978, she recorded the pH of every rainfall, documenting acid rain over the five-year period at the Meteorological Research Institute in Tokyo. 

 

After WW2 the US persisted in testing nuclear weapons at the Bikini Atoll, roughly 4000 km southwest of Japan, and in 1954 several Japanese fishermen became ill after trawling downwind of the testing site. The Japanese government asked the Geochemical Laboratory to investigate. Measuring small concentrations of radioactive elements dispersed in the ocean is quite a difficult technical challenge. Saruhashi and her colleagues used radionuclides to trace ocean circulation about found dispersion was uneven, circulation went clockwise and radiation-contaminated waters went northeast towards Japan, arriving in just 18 months and at much higher concentrations than on the US Pacific coast. Continued testing could contaminate the entire ocean, even if done in such an isolated place. The U.S. Atomic Energy Force was skeptical and sponsored a lab swap, bringing Saruhashi to the Scripps Institute of Oceanography at UCSD so her methods could be compared with those of US oceanographer Theodore Folsom. The two methods gave very similar results and the precision of her methods were undeniable. Her research provided critical evidence to support the end of above ground nuclear testing during the cold war. 

After her positive experience working with Miyake, Saruhashi noticed how differently she was treated as a woman researcher at the University of Tokyo, where she had to prove her abilities, and at Scripps, where her US counterpart Folsom told her not to bother coming in every day and assigned her a wooden hut to work in. Saruhashi believed firmly science and society were linked and that scientists bear social responsibility and should be engaged with the public. She was the first woman elected to the Science Council of Japan, to win Japan’s Miyake Prize for geochemistry. She won the Avon Special Prize for Women for promoting the peaceful use of nuclear power, and the Tanaka Prize from the Society of Sea Water Sciences. She said, “I would like to see the day when women can contribute to science and technology on an equal footing with men.”  She founded the Society of Japanese Women Scientists to recognize women in science and create a venue for discussion of issues faced by women in science as early as 1958. In 1981, she established the yearly Saruhashi Prize, awarded to a woman scientist who serves as a role model for younger women scientists.

She made a lasting impact on our understanding of human impacts on the ocean, climate, and radioactive contamination, blazed a trail for women scientists in Japan and helped foster the next generation of researchers. 

References

Katsuko Saruhashi, Wikipedia, accessed January 2025

Mast, Laura, Meet Katsuko Saruhashi, a resilient geochemist, who detected nuclear fallout in the Pacific, Massive Science, March 22, 2019

Ancient seismology and Chinese polymath Zhang Heng

Detail of linocut 'Zhang Heng' by Ele Willoughby, 2023 on 9" x 12" washi paper. 

This is a linocut print about the ancient Chinese Han Dynasty polymath and statesman Zhang Heng (78-139) who invented a device (a seismoscope, like a simplified seismometer which does not make a record of earth motions) to detect distant earthquakes and indicate their direction, 2000 years ago! I have shown him in blue with a reconstruction of his seismoscope, and a schematic of how it might have worked in bronze, as well as horizontal earthquake surface waves, and Rayleigh waves in particular, in pale pink.

A career civil servant in Nanyang, Zhang Heng (sometimes formerly written Chang Heng) was also an astronomer, mathematician, seismologist, hydraulic engineer, inventor, geographer, cartographer, ethnographer, artist, poet, philosopher, politician, and literary scholar. He was a bit of a controversial figure politically, sparing over calendar reform and with rivals amongst the palace eunuchs. But both his poetry and famous inventions are still remembered. He also improved the Chinese approximation for π and made an extensive star catalog. He understood that the Sun and Moon are spherical, and that the Moon merely reflects the light of the Sun. He also explained the nature of solar and lunar eclipses. He invented the world's first water-powered armillary sphere for astronomical observation; improved the inflow water clock by adding another tank; and, as celebrated here, he invented the world's first seismoscope, which recorded distant earthquakes and their origin (in terms of 8 cardinal directions).

China is a seismically active place, and while the cause of earthquakes remained misunderstood, in 132 Zhang Heng was able to design a device to detect seismicity from distant sources. It was named "earthquake weathervane" (hòufēng dìdòngyí 候風地動儀), and it could roughly indicate where the earthquake came from. According to the Book of Later Han (compiled by Fan Ye in the 5th century), his bronze urn-shaped device, with a swinging pendulum inside, was able to detect the direction of an earthquake hundreds of miles/kilometers away. The outside of the device was described as having 8 dragons with balls in their mouths and 8 open-mouthed frogs around the base which could catch fallen balls (and indicate direction to the source). If there was an earthquake the dragon facing its location would drop a ball into the mouth of a frog below. The Book of Later Han claims that the device was triggered by an event, which was too subtle for people to feel but that the west-facing dragon drop its ball. Officials doubted the device worked as intended, but several days later a messenger arrived from the west and reported that an earthquake had occurred in Longxi (modern Gansu Province). So, the court acknowledged it in fact worked.

Unfortunately, no ancient Chinese seismoscopes have survived and details of the mechanism are sparse. The description of the detected earthquake was written much later. So, we cannot be certain about how it worked precisely; some even doubt that it did. Later Chinese inventors were not able to reconstruct the device. However, a series of modern seismologists have put forward a series of reconstructions. There are several ways a pendulum could trigger a ball to fall. Some of the questions include: was it a regular pendulum? Was it an inverted pendulum? How was its motion transferred to the appropriate dragon and not to any other dragons? How it avoid "false positives" due to other sources of shaking? 

As a geophysicist myself, I find the contemporary reconstructions of Feng Rui and others pretty convincing, so that's what I have illustrated. These scientist argue that the device would have detected horizontal motions due to surface waves which would only be due to earthquakes, and would not be set off by vertical motions (which can be caused by earthquakes or nearby shaking, say, due to people). So they built a reconstruction which they argue is consistent with the description, but detects Rayleigh surface waves. They argue by adding a second ball inside the device, it could have avoided having two opposing dragons triggered. In their model, illustrated in my print, when there is an incoming wave, for instance, from the west, the pendulum would move from west to east. They made a hollow inside, so the pendulum would drop a ball, falling on the west side as it moves off-centre. The ball follows one of 8 radiating tracks, then pushes a lever connected to the dragon mouth and the west-side ball - and no others - would fall. This would correctly identify the direction.

They also make arguments explaining that some reconstructions are not the right style of urn or dragon, arguing that Han Dynasty dragons would have been much simpler than the fancy Ming Dynasty ones shown on some reconstructions. So my illustration tries to respect the archeology of ancient Han artifacts, as well as a mechanism which apparently avoids the pitfalls of previous reconstructions. I also included a waveform, which seismologists will recognize as a horizontal Rayleigh wave (detected by a modern seismograph).

Sources

Zhang Heng, wikipedia, accessed January 2023

Feng, Rui and Yu Yan-xiang, Zhang Heng's Seismometer and Long earthquake in AD 134, Acta Seismologica Sinica, 19, 704-719 (2006)

Feng, R., Wu, Y. Research on history of Chinese seismology. Earthq Sci 23, 243-257 (2010). https://doi.org/10.1007/s11589-010-0720-z

Hong-Sen Yan, Kuo-Hung Hsiao, Reconstruction design of the lost seismoscope of ancient China, Mechanism and Machine Theory, Volume 42, Issue 12, 2007, Pages 1601-1617, ISSN 0094-114X, https://doi.org/10.1016/j.mechmachtheory.2007.01.003.

Zhang Heng Seismoscope, Atlas Obscura 

Jamie Rigg, The ancient earthquake detector that puzzled modern historians, engaged, September 28, 2018

Andrew Robinson, The world's first seismometer used a toad to catch an earthquake, New Scientist, 30 November 2016

Horse Latitudes

I've been reading a cultural history of the sea and it inspired me to illustrate the 'horse latitudes' (with horses galloping across the subtropical highs upon the Pacific, of course).



It is printed by hand on lovely Japanese kozo (or mulberry paper), 11 inches by 12.5 inches (27.9 cm by 31.8 cm), in an edition of 12.

I carved a view of the hemisphere, complete with all the islands and continents in reverse, showing the major trade wind patterns. The winds travel consistently east to west along the hot equator, west to east in high latitudes like the 'roaring 40s', but at the horse latitudes, between 30 and 35 degrees, both north and south, in the region of the subtropical highs known as the horse latitudes, things are not so predictable. It is consistently warm and dry, but winds are variable, which, once upon a time, could be terrifying to sailors. I've illustrated the horse latitudes with actual little horses, galloping around the planet. Since this this print is about the sea, it is the oceans which are 'positive' (printed in ink) and the land which is the negative space. Sometimes we look at the oceans as the space which separates the land masses, but it is possible to have the opposite view or consider the oceans as what connects us all. I love the unexpectedness of this name, and playing with words.

The origins of the term are debated. Some claim that the name comes from sailor's "dead horse" ritual, during which they would beat a straw effigy of a horse and then throw it overboard; they did this to celebrate having worked off their "dead horse time" (the period they were in debt to the paymaster, since they spent their advance pay too quickly, ending up broke by the time a westbound ship from Europe could reach the horse latitudes). Others claim that Spanish colonial ships to the New World, laden with horses, would risk being becalmed in the doldrums or horse latitudes, and when fresh water ran scarce, the horses were the first to go (though this might be a mere folk legend).

The typography of the word horse is designed to suggest the animal, with its mane and hooves. The horses themselves are inspired by Muybridge's early photos, showing their motion. I've also very specifically chosen the view of our Earth. We have many biases in maps; we expect north to be up, but that's arbitrary, and here in North America we expect to see the Americas on the left (because we read left to right). But, in this print, it's all about the Pacific, so it goes in the middle.

I'm really proud of writing that description without feeling compelled to try and first explain about Hadley cells. That took restraint.

Frack

Funky music, animation and science journalism - nice.

Speaks for itself, I think, so I'll just say drinking water should not be flammable. Ever.

(via bioephemera)

*waits quietly for inevitable BSG jokes*

and while we're at it, happy Earth day!

Mercator knew a thing or two about his environment, and scale, and the disruption caused by people, so he's here today to remind us to be kind to our planet. He's printed in water-soluble ink on kozo paper (from leaf fibre rather than wood pulp, so it's more easily renewable), by the way.

Earthquake seismology great Inge Lehmann

The Mad Scientists of Etsy theme for the month of April is Earthquake Seismology. This was inspired to honour the victims of the Japanese earthquake and tsunami. I decided I did not want to make art about the destructive power of earthquakes. (I'm offering a copy of my moku hanga woodblock print with all proceeds to the Canadian Red Cross for relief of those effected by the disaster. I hope this is more constructive an approach.).

I had been thinking, rather, for some time, of doing a portrait of Inge Lehmann (1888-1993), a Danish (or, as she put it the Danish) seismologist who was at the forefront of the field in the early twentieth century. In 1936, she wrote a paper, entitled simply P', in which she laid out her arguments supporting her discovery of the inner core of the earth.



We now know, as she first postulated, that the earth has roughly three equal concentric sections: mantle, liquid outer core and solid inner core. The crust, on which we live is merely a thin, um, scum really, on top of this slowly boiling pot. The only way to probe deep into the earth's core is to employ massive earthquakes, the waves they generate and the paths they follow. There are two main types of seismic waves used for studies of the globe, unimaginatively named Primary (or P, or compressional) and Secondary (or S, or shear). Imagine a glass of water with a straw; the straw will appear broken at the air-water interface, because light bends as it enters the water. Just like light travelling through different media, these seismic waves can bend, reflect or be transmitted at any boundary. The difference in physical properties between the mantle and outer core causes a P-wave shadow. (For S-waves, the shadow zone is absolute because liquids, like the outer core, do not support shear - imagine trying to cut water with a pair of shears and you can see this for yourself. Thus, no shear waves can make it through the outer core, and thus we can be certain the outer core is fluid). That means, the compressional waves from an earthquake can be recorded at seismic stations out to 105^o from an epicentre and then there is a zone which is in the core's shadow. Lehmann found that there were some late-arriving P-waves are much larger angles (142^o to 180^o) which had been vaguely labelled 'diffractions'. She showed that these could be explained instead by deflections of the waves which travelled through the outer core at her postulated inner core boundary.

She later discovered a discontinuity in the mantle (confusingly also called the Lehmann discontinuity). She did important work well into her 70s and lived to be 105.

When she received the Bowie medal in 1971 (she was the first woman to receive the highest honour of the American Geophysical Union), her citation noted that the "Lehmann discontinuity was discovered through exacting scrutiny of seismic records by a master of a black art for which no amount of computerization is likely to be a complete substitute..." (1, 2).

I think her accomplishment is downright astonishing. To have the exactitude to work with the data and the daring to neglect the irrelevant and offer up a simple, elegant - correct! - explanation is a rare and marvellous thing. To be the top of her field in 1936, when she was a pioneer for women in science and had to compete in vain with incompetent men (her words,1) is heroic.

There are a grand total of two easily found photographs of Lehmann I was able to find on the internet. I based my portrait on the earlier one, to match the date of her phenomenal P' paper. I also show her model of the earth in red-orange ink, complete with mantle, inner and outer core, and travel paths for rays through the layers, including into the shadow zone.

8.9

I keep checking the news to see updates on the aftermath of the magnitude 8.9 event off Japan's Honshu Island last night (or afternoon locally, 2011 March 11 05:46:23 UTC). The initial estimates of lost of life were far too low for an event of this magnitude which triggered a tsunami. It's beyond Hawaii now, but tsunami warnings were issued throughout the Pacific, including coastal BC. The problem is the nature of the coastline, as people in Port Alberni, where a 1964 tsunami swept away homes and swamped businesses, know well.



Though I don't have any instruments in the water which could sense the wave, at the moment, people still called me at the crack of dawn. I don't envy friends who work in earthquake seismology or in disaster preparedness on days like these.* I'm glad the epicentre was not further south - closer to larger population bases and known significant gas hydrate deposits. There are fears that earthquake shaking could destabilize gas hydrates, which may both hinder slope stability (another tsunami risk) and release large amounts of methane.

*For the most seriously affected people: Médecins Sans Frontières and the Canadian Red Cross can be found at these links.

(figures from Bunting et al., The Science of Tsunamis, Oilfield Review, 2007)

Saint Lawrence River

Wind-farm