|The Simple English Wiktionary has a definition for: debris.|
Debris in a general sense means man-made garbage.
The average American produces garbage, also called trash, at the rate of four pounds per day per person, which translates to 600,000 tons per day, or approximately 220 million tons per year. This is almost twice the rate of trash generation per person as most other major countries. Trash levels can be reduced primarily by recycling, re-use, and reduced consumption.
Other websites [change]
Miller, 1989, Potential Hazards from Future Volcanic Eruptions in California: USGS Bulletin 1847: