Lava tubes: summary

So, to summarise what I've been writing over the last week:

1. Lava tubes are natural tunnels formed by flowing lava.
2. In some places, they have collapsed to form rilles.
3. On the Moon they are roughly an order of magnitude larger than their equivalents on Earth.
4. They offer considerable protection for a manned base from a variety of environmental dangers.
5. Lava tubes would provide an ideal location for a the base for a mission lasting longer than a couple of days.
6. Satellite photography can be used to look for intact lava tubes indirectly by looking for discontinuities in rilles.
7. GPR can see lava tubes directly, but has serious problems associated.
8. Geophones can generate precise data on lava tubes, but require a network of sensors and a number of shock waves in different places.
9. "EMP thumpers" combine the advantages of geophones and GPR, but is still under development as a technique.

Tomorrow I will begin to discuss problems (and their possible solutions) associated with staying on the Moon for any length of time.

By the way, a disclaimer: writing these articles is part of a learning process for me. I don't suggest that they're even factually correct (although I do my best). If you find them useful, then great! And if you find any problems with them please let me know.