SEATTLE (AP) — Officials briefly issued a tsunami warning for parts of Oregon and California after a powerful earthquake struck off the coast.

That warning ended up passing without any signs of a tsunami – but Washington state’s seismologist said issuing a warning was still the right step.

The earthquake itself had a magnitude of 7.0 and was felt for hundreds of kilometers along the coast.

“The tsunami warning was, in my opinion, completely correctly issued,” said Harold Tobin, director of the Pacific Northwest Seismic Network and a Washington state seismologist. The quake occurred close enough to shore to pose a serious potential danger.

A magnitude 7.0 earthquake is classified as severe and can cause severe damage.

Geologists later learned that the quake was a so-called “strike-slip” earthquake, in which tectonic plates move side by side. This type of earthquake does not have as much of an impact on raising water as other types of earthquakes.

“This is less likely, but not impossible, to trigger a tsunami,” Tobin said.

There are four levels of tsunami-related notifications that the government can issue depending on the potential severity of the wave. The most serious is the tsunami warning, which indicates the potential for widespread flooding. Warnings alert the public that coastal flooding and strong rip currents are imminent, expected or occurring, which may continue for several hours after the first wave arrives.

Here are the other levels:

• A tsunami warning is issued when strong currents and waves are dangerous to people in or near the water. However, no significant flooding is expected at this elevation. At this level, officials can close beaches, evacuate ports and marinas and move ships to deeper waters if there is time.
• A tsunami warning is issued if a tsunami could hit the monitoring area at a later date. Monitoring can be upgraded to a warning or advisory or lifted based on updated information.
• A tsunami information statement is issued when an earthquake or tsunami has occurred. In most cases, an information statement is issued to reassure people that there is no risk of a destructive basin-wide tsunami or that evacuation is necessary.

Tobin said officials likely issued the warning because of the potential severity of a tsunami resulting from such a large earthquake and then monitored the water either via buoys or along the shoreline to look for possible tsunami waves. When nothing came, the warning was lifted.