Moon Rocks, Geoengineering and a Hawaiian Earthquake: Geoscience 14-20 March 2019

This week (14-20 March, 2019) I have an eclectic selection of news items from the world of geoscience, so much so that it’s hard to find any theme that links them. If pushed, though, I’d have to say that the thing they have in common is that they have associations with large scale processes — and even that is a tenuous link.

So what are they? Well, this week I’ve been intrigued by potential new information from the Moon; a glance at how anthropogenic activity might be used to redress some of the changes humans have made to our Earth system; and a visit to our old friend from last year, Kilauea.

A New Look at Moon Rocks

Some geoscience stories are routine; some, especially those involving catastrophic damage or loss of life, are disturbing and distressing; and a very few send shivers of excitement down the spine. One of these appeared in the media this week with the revelation that NASA have selected teams of scientists to conduct experiments on moon rock samples that have been sealed and untouched since the return of Apollo 15 in 1971 and Apollo 17 in 1972.

The rationale for holding these samples back is a sensible one, given that technology (and our understanding of the lunar environment) has advanced since that great leap for mankind. Quoted on NASA’s website, the agency’s Lori Glaze described it as: “…an investment in the future. These samples were deliberately saved so we can take advantage of today’s more advanced and sophisticated technology to answer questions we didn’t know we needed to ask”.

The selected research teams will consider topics that even the most sensational reporter would struggle to make exciting to the layman — topics such as “how curation affects the amount of hydrogen-bearing minerals in lunar soil” or “how airless bodies are affected by exposure to the space environment”.

There are unlikely to be earth-shattering results because, as NASA points out, the samples are really only a snapshot. “NASA has only collected samples from a few places on the Moon so far, but NASA knows from the remote sensing data that the Moon is a complex geologic body”.

There is surely far more to be discovered from possible future missions. The eventual outcome, however, should significantly enhance our knowledge of the Moon and the processes which shaped it. And as we learn more about our nearest neighbour, we will also gain some understanding of how we might approach: “the next era of exploration of the Moon and beyond”.

Geoengineering: A Complex Issue

Climate change remains a matter for considerable debate but it probably isn’t too contentious to say that the scientific community has come to a consensus on the matter — that the climate is changing and that it has serious implications. The problem of how to address it can be tackled (broadly) from two directions — reducing the activities that cause it, and engaging in activities that modify it.

The second of these involves geoengineering, defined (by the website Geoengineering Watch) as: “the artificial modification of Earths climate systems through two primary ideologies, Solar Radiation Management (SRM) and Carbon Dioxide Removal (CDR)”.

There are numerous studies ongoing in this area, so the one that was published this week should be regarded as indicative of the benefits and the complications of the processes. Most of these studies are modelling-related and this one, published in Nature Climate Change and focussing on the impact of injecting aerosols (minute particles) into the stratosphere, is no exception.

It can’t be said often enough that change in one part of the Earth system will have implications elsewhere and this is what the study considered, addressing the issue that: “Solar geoengineering (SG) has the potential to restore average surface temperatures by increasing planetary albedo, but this could reduce precipitation. Thus, although SG might reduce globally aggregated risks, it may increase climate risks for some regions”.

The study addresses the effects of the process rather than its practicalities (another subject entirely) but the results are encouraging, indicating that the perceived problems, while certainly not insignificant, are perhaps not as great as they could be. “…while concerns about the inequality of solar geoengineering impacts are appropriate, the quantitative extent of inequality may be overstated”.

A(nother) Hawaiian Earthquake

Last year, you may remember, I ran the digest for several weeks keeping up to date with the eruption of Hawaii’s Kilauea volcano. It was an eruption that was characterised by repeated earthquake activity, with regular tremors of around M5 occurring as explosive eruptions shook the heart of the volcano.

The eruption officially ended in September 2018, a clear six months ago — so what are we to make of this week’s M5.5 earthquake on the south flank of the volcano?

The answer is that residents of the area around Kilauea can rest easy. The earthquake wasn’t caused, as that series of events last year was, by movement of magma but by the mechanical readjustment of the land in response to large-scale processes. “The location, depth, and waveforms recorded as part of today’s earthquake are consistent with slip along [a] south flank fault” notes the official report on the Hawaiian Volcano Observatory website.

This movement, in other words, is normal. “We see no detectable changes in volcanic activity at the summit or along the rift zones of Kīlauea as a result of this earthquake, Aftershocks are possible and could be felt”.