This week I’m giving my (now regular) summary of activity of activity at Kilauea — something which becomes more relevant, I think, as the main eruption drops further down the news agenda. But I’m also having a quick look at something that is prominent (some may say too much so) in news feeds around the world, as well as a quick look at a very specific application of geoscience.
The United States Geological Survey’s Kilauea updates are still popping into my inbox twice daily, which means there’s still plenty going on, although there’s been no significant change in activity over the past week. In other words, the key features are the eruption of lava, occasional explosive activity at the summit and the emission of gases and volcanic particles.
Lava continues to be the most spectacular output of the eruption, and although only one of the 23 fissures generated during this eruption remains active, it offers an extraordinary display of the force and scale of the eruption. The embedded video shows the almost incredible speed at which lava is currently flowing from fissure 8 down towards the sea.
The USGS update is, to my mind, a little understated about this, noting that: “The size and shape of the flow field is virtually unchanged since the morning of Monday June 18, with the exception of an additional 28 acres”. On a topical note, that’s roughly the area of 14 football (soccer) pitches and it’s how much the land area of Hawaii has grown since Monday.
While volcanic gas emissions remain high, there’s at least one unusual and volcanological curiosity emerging from Kilauea this week — Pele’s hair. Pele is the Hawaiian volcano goddess and this poetic name is given to fragments of volcanic glass. As lava moves, some of it can break off and stretched or spun into strands of which can be up to two metres long.
These strands are light enough to be come airborne, with the smaller ones travelling for tens of kilometres, and are potentially hazardous because of the irritation they can cause to skin and eyes, although at Kilauea the majority of this deposition is close to the vent of fissure 8.
A Case Study in Hazard Management
I have said before (often) and I suspect I’ll say again that what makes a volcano, or an earthquake, or any other natural and potentially devastating event dangerous is not the event itself but the danger that it poses to nearby human populations — in other words, the risk of damage.
Risk varies. Again, let’s talk volcanoes. Eruptions can’t be stopped but they can be managed. A volcano like Kilauea, where eruptive style is localised and where there is enough warning to allow the local population to be evacuated, may cause a lot of damage but the risk to humans is low. At the other volcano which has erupted recently, Fuego in Guatemala, the eruptive style is very much more violent, occurs with much less warning and, as a consequence, has a much higher risk. That goes some way to explaining why Fuego’s recent eruption killed dozens, while at Kilauea no lives have so far been lost.
Because volcanoes, earthquakes, tsunamis and the like can’t be predicted and can’t be stopped, the key to minimising deaths, if not damage, is preparedness. Now, I fully admit to being a bit of a geek on this subject, but I did find a document this week which is not overlong but does summarise some of the ways in which a government can mitigate risk from a wide variety of sources.
All governments do (or should do) this, but this one, for Chile, is very accessible and worth a read if you want a simple introduction to risk management in practice. Chile has more than its fair share of significant natural hazards, being vulnerable to the regular occurrence of earthquakes, tsunamis and volcanic eruptions, among others.
I may be going a bit off-topic with this piece, but for me it illustrates the fact that understanding the science of a natural event is the key to managing both the hazard itself and the ensuing risk — and, in the end, saving lives.
The Earth Moves For Mexico’s Football Fans
The language of the natural hazards is descriptive and regularly used in colloquial speech. Violence erupts…the markets are flooded…and did the Earth move for you? (Don’t answer that: it’s a rhetorical question.)
Sometimes, however, the sports fan’s passion and real science do come together. I’ve mentioned, in my earthquake digests in the past, that significant moments in sporting events can generate local seismic signals causing the ground to shake — though I should note that a seismic signal doesn’t necessary mean that there has been an earthquake (something headline writers need to be a little more careful about).
The reports on the “earthquake” which registered when Mexico scored against world champions Germany was widely reported, but not all of the reports picked up on something which is a reminder of the particular problems that Mexico City has in terms of earthquake risk — the distance over which the signal travelled.
A report quoting Mexico’s Institute for Seismologic and Atmospheric Research this week pointed this out. The signal travelled further than usual because of the underlying geology. Mexico City is built upon lake sediments which amplify a seismic signal.
It’s a curiosity for football fans, but it’s a significant problem for the population — because the same amplification occurs when a real earthquake strikes, and that means that moderate earthquakes can cause a disproportionate shaking and, therefore, a disproportionately high level of damage, as the devastating earthquake in Mexico in 1985 demonstrates.
The lesson is the same as in the section above. Understanding the science helps to manage the risk.