Across
- 4. the branch of science concerned with earthquakes and related phenomena.
- 6. tectonics a theory explaining the structure of the earth's crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates which move slowly over the underlying mantle.
- 7. relating to, involving, or requiring an absence of free oxygen.
- 8. each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei
- 9. physical rather than biological; not derived from living organisms.
Down
- 1. the time taken for the radioactivity of a specified isotope to fall to half its original value.
- 2. a large stable block of the earth's crust forming the nucleus of a continent.
- 3. relating to or resulting from living things, especially in their ecological relations.
- 5. a meteor that survives its passage through the earth's atmosphere such that part of it strikes the ground.
- 7. relating to, involving, or requiring free oxygen.