Crust thickness of anywhere
A start at story telling.
Why?
What is under your feet?
Crust thickness is a start at story telling. I'd love to be able to say "You're where? In Boston? Ok, you are standing on glacial till (link), atop mumble from mumble, and mumble (n km), and Grenville basement (link)". But... I've not seen such data. So... small steps.
Fun
Can you find... somewhere with 10km of sediment? Two places with crust thicker than 60 km? What else?
Any questions?
... Mark it up!
Caveats
- The colors in the crust side-views are all bogus.
- The thicknesses are approximate. There is both averaging and quantization error. It's a 2°×2° grid (2° is up to ~200 km). And the numbers are quantized (with quant errors of maybe 1 km sediment, and less than 5 km crust).
- Deeply subducted crust, descending into the mantel, is not shown. :(
- The shallow water is false color. You can't see through lots of water.
- The atmosphere (clouds) is not shown.
- The snow and veg are for a June. Your June may vary.
The data
The CRUST2.0 dataset provides crustal thickness on a 2° global grid.
Crustal Model CRUST 2.0
~gabi/ftp/crust2
REM -- REM Subgroup 5 / Crust 2.0
Gabi Laske (UCSD)
USGS outreach
The CRUST2.0 elevation data is from ETOP05.
A new CRUST1.0 (1° grid) is in development.(2011-2012)
Earth image: NASA Visble Earth
Additional credits: three.js,jQuery.
The code
crust20.js is a javascript encoding of depth data from CRUST2.0 (obtained 2012-02). It includes depths for ice, water, soft and hard sediments, upper, middle and lower crust, on a 2° global grid. The CRUST2.0 elevations were derived from ETOP05, and I've rounded them to 1 km.
The demo
Doables: A transect line should be drawn on map and globe. Mention cross-section scale/length (1 Mm). Unintended white lines on cross-section - bug or feature? When the globe is upside-down... how confusing is everything? Mousing the cross-section could control display. Mousing the key could highlight cross-section layers (to better see thin layers). The cross-section could be zoomable. The cross-section could be interactively specified (click-drag drawn on the map). Tweak colors to improve distinguishability (water vs crust, ice vs background). Gracefully handle moving along map edge. Make globe surrounding non-selectable. Is globe rotation and control discoverable? Test on tablet.
Doables: The demo code could be isolated, to encourage contribution, adoption, and takeover. And componentized for mashups.
-announce