9 January 2017
Let’s start off the new year with something fun and volcano-related! Remember a couple of months ago when Google Earth Timelapse got updated? I didn’t spend a lot of time looking at it back then, but I’ve taken it for a spin since then and – being a volcanologist – decided to look at volcanoes. And it turned out to be a lot of fun.
A quick overview of Timelapse: It actually came out in 2013 and was the result of Google working with the U.S. Geological Survey, NASA and TIME to compile a history of satellite imagery (including Landsat, Sentinel and MODIS) of the period between 1984 and 2012. Last November, they updated the project with sharper images and four more years’ worth of them, extending the range to 2016.
The home page for Timelapse shows some of the choice examples of why this is useful and cool: you can watch urban growth, land use change, the effects of ongoing climate change on glaciers, coastal erosion and barrier island migration, and a whole host of other things that are best observed through long-term satellite images. But the best part of the project is that it doesn’t just cover a couple of spots, it covers the entire planet. You can look at whatever you want, cloud-free, for more than three decades, and that’s pretty darn impressive. (It’s not quite at the resolution of the DigitalGlobe satellite images that get used for Google Maps, but that’s an ongoing tradeoff of satellite imagery: you can have detail or you can have repeated surveys, but you can’t have both without a whole host of dedicated satellites. While initiatives like CubeSats may change this eventually, the really good imaging satellites are, for now, expensive, big and limited in number.)
Naturally, given a new cool toy like this, I chose to use it to look at volcanoes.
Like the Island of Montserrat, where lava dome-forming eruptions have been going on since 1996, destroying much of the southern part of the island (and the capital city of Plymouth):
My own field area in Guatemala, the Santiaguito lava dome complex (watch the last couple of years, where you can see some big channelized lava flows forming on the southern slopes of the domes):
The Big Island of Hawai’i, where Kilauea Volcano has added quite a bit of land in the form of lava flows. (The timelapse is almost perfectly timed to the beginning of the ongoing eruption there, which started in 1983, but it gets really interesting in the past few years with the new lava lake at the summit):
Mount St. Helens. Unfortunately the images miss the 1980 eruption, but you can see the re-awakening of the volcano in 2004 and the subsequent four years of lava dome growth and activity:
And Mount Pinatubo, where the huge 1991 eruption was followed by decades of mudflows that formed from the massive amounts of ash and rock that were deposited. This one is especially cool for looking at land use change – it illustrates both where the mudflows made farming unsafe and where people moved afterward to continue farming:
I can imagine these being a really excellent teaching tool, particularly for basic lessons about landscape evolution – it’s always more interesting when you can use familiar terrain for a lesson, and the Google Earth interface makes it easy to look at pretty much anything you want.