There are many factors to consider on why a market can fall and this may not only have to be by 30% fall, it could go beyond or below that range, depending of the situation that caused for the fall, I will itemize on some fee factors I know could cause on such from below.

1. Economic Breaking News
2. Crypto market arket demands and supply
3. Hypes for dump and pump by whales
4. Market season, bull or bear season.
5. Market Cap and active quality investors.