A powerful earthquake off Russia’s east coast triggered tsunami waves across the Pacific, prompting alerts in Hawaii and California.

Russian agencies have warned a new powerful earthquake near the Pacific's Kuril Islands could trigger a tsunami wave up to 19 centimeters (7.5 inches). A magnitude 6.8 earthquake hit Russia's Kuril islands on Sunday, according to data from the U.S. Geological Survey (USGS). The Pacific Tsunami Warning System gauged the quake at 7.0.

Russia’s magnitude 8.8 earthquake spawned serious tsunami warnings, but waves have been moderate so far. Here’s the geological reason why