A drum of earthquake is a magical drum. Applying a charged drum of earthquake will create several pits around and possibly under you, anger nearby peaceful monsters, and wake up (and possibly scare) all monsters on the level. This will "produce a heavy, thunderous rolling!" A drum with no charges behaves like a leather drum.
The pits created by a drum of earthquake can destroy altars, even on undiggable dungeon levels. This is the only way to destroy the unaligned altars in the Valley of the Dead and Orcus-town. The high altars in Moloch's Sanctum and the Astral Plane are unaffected.
The drum of earthquake is a quirky item, to say the least. Its results are not unambiguously bad, but it is still hard to come up with good uses for it. Aside from applying a wand of digging, it is perhaps the only item in the game capable of opening pits under squares the character is not currently standing on, but the number and distribution of the pits is randomized, so it can not be used to open a pit on a specific square. Perhaps some future genius will work out a brilliant drum of earthquake-based strategy that dominates the game, but until that happens, here are some ideas:
- Shake hidden monsters off the ceiling
- Trap monsters in a pit(maybe) and pound them with a polearm or fire missiles at them in relative safety.
- If levitating, create an obstacle course to slow monsters pursuing you.
- Save it for polypiling; the drum is a magical tool, and may turn into a magic marker.
- Unblock some Sokoban boulders if the scroll of earth you read was not cursed after all.
- Unload it in Moloch's Sanctum after grabbing the Amulet. Satisfying, but not really helpful in game terms.
- At a high level, it can be useful to immobilize most non-flying monsters on a level, for instance the aligned priests and player monsters on the Astral Plane.
- Attract the rogue quest nemesis (stand at the bottom right square of the left segment of the level, and as long as you are at least level 13 the assassin should wake up).
- Perhaps the most useful application is to use it to awaken the Wizard of Yendor without having to do the Wizard's Tower.
It can also be used as an ordinary leather drum: to awaken sleeping monsters from a distance. For example, it will awaken the Chromatic Dragon on the Caveman quest without requiring the player to leave the downstairs square. The aesthetic effect of using a drum of earthquake for this particular task (opening perhaps dozens of pits on a large, open level) is also quite pleasing. The Wizard of Yendor will also spare you some digging if summoned this way.
Pacifist players will probably empty this instrument in a safe area because they would risk breaking conduct by opening chasms under monsters. As a leather drum, it is great to un-freeze pets that have attacked a floating eye.
Many travelers have seen the drums of the great apes, and
some have heard the sounds of their beating and the noise of
the wild, weird revelry of these first lords of the jungle,
but Tarzan, Lord Greystoke, is, doubtless, the only human
being who ever joined in the fierce, mad, intoxicating revel
of the Dum-Dum.