Types of Seismic Waves Explained | Britannica

National Park News on Instagram: "A seismic swarm that shook Mount Rainier with about 1,300 earthquakes has quieted down. Scientists say earthquake activity is now back to normal background levels, about 10 tiny quakes per month, which is typical for the Washington state volcano. The swarm that started July 8 was caused by Rainier’s hydrothermal system, not magma movement, which would indicate a volcanic eruption. At its peak, there were about 40 quakes per hour, according to the USGS. The large