Here's a cool demo I saw recently that allows a cyclist to specify risk tolerance for busy roads, based on traffic data. Take the direct, busy route, or the roundabout way, using bike paths where available.
I'm looking at a legal agreement on my desk to lease 120 acres of productive eastern Nebraska farmland to build a commercial scale solar project. The land would be taken out of production ("sacrificed") for the 50 year lease, with payments about twice what the land leases for for agriculture (soybeans).
Here's the LK-99 tie in: the most precise gravity meters in the world are superconducting meters, which require a lot of power (2 kW contonuous) to maintain a helium dewar at 4K. It's tough to make that a field instrument. A compact, stable, room temperature gravity sensor would be a huge advance for hydrogeophysics.
The MEMS accelerometers in our phones are in theory sensitive to gravity changes, but they're not nearly sensitive enough. This group is trying to improve the MEMS sensing technology, but it's doubtful it will be as good as classical gravity meters (falling mass, or spring) or quantum (BEC) ones:
One important distinction is between measuring gravity (generally, acceleration in the vertical direction) and the gravity gradient. The latter is generally easier and more useful for navigation.
Navajo Generating Station, which was the largest coal-fired ppwer plant in the western U.S. and powered CAP pumping stations, closed in 2019 along with the accompanying coal mine.
Speaking of Albuquerque, this just-published paper shows how measuring the change in acceleration due to gravity can be used to map aquifer storage change. Importation of San Juan River water has made a big difference.
Microgravity surveying is great for this and other geo applications. I know of many geothermal fields mapped the same way to monitor fluid level and steam migration.
Good stuff!
Too bad Google gets the credit for the amazing https://www.shakealert.org system developed by the USGS and other public entities. Altering the user is the easy part, detecting the earthquake is the hard part.
Android also has a "detection" feature in non ShakeAlert locations. Android phones' accelerometer is used to detect earthquakes and warn other phones in the area: https://crisisresponse.google/android-alerts/
Oh but if you're truly committed you'll need to avoid Cloud computing resources, avoid Twillio, don't use any Google services, no Firebase Cloud messaging... You probably shouldn't use Android phones either...
And remember any delayed or failed messages put people's lives in danger...
Or we can just admit that Google as a whole had some impressive achievements here alongside the Earthquake team.
I thought it was fair given their oversimplification of what delivering messages at scale requires.
The point isn't that the Earthquake Detection isn't impressive. Why do we have to deny Google any credit here? Is it just because they're a big tech company?
IMO it feels like another "I could build Dropbox in a weekend" comment.
They are not allowed in all states/areas. So you might be someplace where they are not allowed, or close enough that there isn't a good place to stop and put them back out. I see them in use all the time, but that is a reflection of where I live.
Basically you can image anything if there is a density contrast, it's "just" a matter of how good your sensor and inversion algorithm is.
I spend my day-to-day working on measuring gravitational changes to determine groundwater storage change. There's a huge difference between demonstrating something in the lab vs. building an actual field instrument you can use in the real world.
The datasets you pick from can be a bit confusing unless you click the (!) icon next to the names to figure out what they are.
I have mostly used it for looking at old reconnaissance satellite images from the 70's and 80's. I posted some directions here and a image from a satellite.
https://rc.nau.edu/cranc/?profile=ibc&layer=OpenStreetMap