1.
earth and sand; soil and gravel; sediment; debris
A mixture of soil, sand, gravel, and rock. Often used in the context of natural disasters like landslides and mudflows, as well as construction.
Usage
Frequently appears in weather reports and disaster news in Japan, where heavy rains often cause landslides. Key compounds include 土砂崩れ (landslide), 土砂災害 (sediment disaster), and 土砂降り (downpour — using the same characters but with a different meaning).
土砂降り (torrential rain) uses the same first two characters but is a separate word with a different meaning.