Hey there from CNN. I'm Krista Bow with The Five Things You Need to Know for Wednesday, July 30th.

Most tsunami warnings in the U.S. have now been downgraded to advisories.

After waves created by a powerful earthquake in Russia made it to the west coast.

But a meteorologist from the National Weather Service says it's still important that people stay vigilant.

We asked CNN's Brandon Miller to put the quake and tsunami warnings into perspective.

Well, Krista, it takes a massive earthquake to trigger a basin-wide tsunami through the entire Pacific,

and that is exactly what we had last night.

The magnitude 8.8 that struck just before 7.30 p.m. Eastern time last night

was tied for the sixth strongest ever recorded and those records go back over a hundred years.

Quakes this strong happen about once per decade and it was a mega thrust quake which gets its name because the Earth's crust literally thrust upwards the moment the quake occurs.

It's that upwards thrust which was incredibly strong since the epicenter of this quake was very shallow,

only about 10 miles below the ocean floor.

That pushes all of that ocean water, up above it, and out, forming the tsunami.

Just like if you were in a swimming pool and you pushed your hands into the water to create a wave,

that wave will continue to move and spread out until it fills the whole pool, or in this hands into the water to create a wave, that wave will continue to move

and spread out until it fills the whole pool, or in this case, the Pacific Ocean.

The U.S. and India launched a first-of-its-kind satellite this morning that could change the way

we see Earth and how we respond to natural disasters. It's called NASA-Isrow Synthetic

Aperture Radar Mission, or NYSAR for short.

CNN's Tom Foreman has the details.

This satellite goes up there with this unique radar.

It can look through clouds, it can look through tree cover.

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