It was tempting, this week, to go a little off-piste (or rather, off-planet) and talk at length about space exploration — because, as we know the Earth system is much more extensive than just the Earth. But this week’s launch of Falcon Heavy rocket has been covered extensively by people who know far more about it than I do, so I’ve decided to look at some of the things that are equally interesting but perhaps not so headline-grabbing.
Taiwan Earthquake: M6.4
The first thing to note is something that did make headlines, and that’s a significant and deadly earthquake which struck Taiwan on the 6 February, killing at least four people (numbers reported at the time of writing) and with many more injured.
Taiwan is in an awkward place, tectonically, caught at the junction between three tectonic plates — the Philippine Sea, the Eurasian and the Sunda plates. With this in mind, it’s hardly surprising that there’s regular earthquake activity there, and this week’s, according to the United States Geological Survey, resulted from: “oblique strike-slip faulting at shallow depth, near the plate boundary between the Philippine Sea and Eurasia plates at the northeast coast of Taiwan”.
The earthquake is the largest in a series (22 of at least M4.5 to date) which began with an M4.8 on 3 February, 2018 and led to the mainshock (assuming, of course, that no larger tremor occurs) on 6 February. The earthquakes continue with nine aftershocks currently expected and more remaining.
It’s not easy to describe an earthquake series. By definition, the mainshock is the largest magnitude and cannot be determined until the earthquake series is deemed complete. Not all earthquakes are preceded by foreshocks, or followed by a series of aftershocks. While it’s not unreasonable to expect more aftershocks following the Taiwan ‘quake, it may also be the case that the M6.4 is, itself, not the largest in the series but another may be to come.
Geoengineering and the Next Big Eruption
Okay, I’m going to break all my rules and oversimplify a hugely complicated subject by using a single study to illustrate a point. But something caught my eye this week, and it was a study about global cooling. Large volcanic eruptions generate significant emissions of sulphur dioxide which help to reflect the sun’s heat and reduce the temperature. It’s not huge in terms of degrees and it’s not permanent, but it can be significant — and potentially disastrous — in the short term. There are numerous documented occurrences of volcanic eruptions cooling the Earth.
Perhaps most notoriously, the Laki fissure eruption in Iceland in 1783-5 gave us crop failures and famine (and, some say, precipitated the French Revolution); and not that many years later the eruption of Tambora, in Indonesia, in 1816 gave the world the “Year Without a Summer”. More recently, in 1981, the huge eruption of Mount Pinatubo in the Philippines lowered global temperatures by a degree.
The implications of a future eruption on this scale, in terms of food production on a crowded planet, are significant. So an article in the New York Times about geoengineering caught my eye. This was a a proposal by NASA and others to try and offset the results of a future volcanic eruption.
The article itself isn’t detailed and it doesn’t focus on any specific strategy, beyond data collection. But the reason I’m flagging it up is that volcanic hazard is defined by the numbers of people affected rather than by an eruption itself. A really large eruption will affect an awful lot of people — and the authorities are beginning to look at what, if anything, they can do.
Oklahoma: The Definitive Answer?
If you’ve been reading the earthquake digest over the years you’ll know that I kept coming back to the ongoing swarm of minor earthquakes in Oklahoma. Oklahoma ought to be tectonically stable, and a series of studies have indicated that the tremors occurring there are the result of human activity — specifically, the injection of waste water into the ground.
I’m always wary of describing any single study as conclusive, but this week new research from the University of Bristol has revealed further strong evidence to indicate the link between wastewater injection and earthquake activity.
There doesn’t appear to me to be anything startling here — just a different methodology producing additional evidence to substantiate what seismologists already know. But Oklahoma’s earthquakes give an alternative perspective on geoengineering — and that’s that straightforward engineering, in the oil and gas extraction process, can have unintended consequences.
Technology can have negative impacts, too.
Volcano Cup Update
If you haven’t been following the #VolcanoCup, here’s your update. We’re still in the early stages: the US group for the knockout stages has been confirmed as Crater Lake, Mount Rainier, Mount St Helen’s and Kilauea (which knocked out my favourite, Yellowstone, in a thriller).
What makes this so interesting is the reasons people give for their votes. Someone voted for Mt Rainier because it’s “a looming bringer of disaster”, someone else: “Just voted Glacier because I never heard or read about it”.
The latter point is probably the most important. The Volcano Cup’s initiator, Dr Janine Krippner, gives her reasons for setting it up as follows: “Millions live around potentially active volcanoes & many more travel to them. There are >1500 potentially active volcanoes around the world, we need to arm people with knowledge about hazards & where to get good information”.
The three other sections of this article have shown how geography and geology impact upon us. Knowing and understanding why and how can be a very serious business, and initiatives like the Volcano Cup are an excellent way forward.