Hot dry rock geothermal energy makes use of hot fluids found naturally in basement rock; but such HWR conditions are rare. By far the bulk of the world’s geothermal resource base (over 98%) is in the form of basement rock that is hot but dry—with no naturally available water. This means that HDR technology is applicable almost everywhere on earth (hence the claim that HDR geothermal energy is ubiquitous). Typically, the temperature in those vast regions of the accessible crystalline basement rock increases with depth. This geothermal gradient, which is the principal HDR resource variable, ranges from less than 20 °C/km to over 60 °C/km,
Note from the Underground (Buffy comic) return Sunnydale to its natural state. Buffy rescues Xander and Dawn from The Scourge. Buffy must fight for her friends' and family's lives, and also for the right to live her own life, Faith and Angel help. "Buffy" comics such as this one are not usually considered by fans as canonical. However, unlike fan fiction, overviews summarizing their story, written early in the writing process, were approved by both Fox and Joss Whedon (or his office), and the books were therefore later published as officially Buffy merchandise. Note from the Underground (Buffy comic) "Note from the Underground" is a story