We continue to follow breaking news for you this morning. Just frightening scenes coming out of Japan on this New Year's Day. Japan's West Coast, reeling after a powerful 7.5 magnitude quake caused widespread damage, triggered tsunami warnings and four-foot tsunami waves. This is the moment that the quake struck just a few hours ago. You see that building crumbling to the ground on the screen's upper left side there. Take a look at the scene from inside of an office building.

It's the first time I'm seeing this video. You can see just how long it goes on and just how violent that shaking is. I think it's more than one thousand.

Thousand thousand.

At this bowling alley, you can see people racing for cover underneath the tables there.

Now, the 7.5 magnitude quake struck Japan's western Coast. We know that Japanese officials warned people to get to higher ground in case of a tsunami. Thousands of military personnel are on standby.

Again, yeah, the West Coast of Japan, about 180 miles from Tokyo. Tens of millions of people don't have felt this in Tokyo, but the epicenter was in the less populated Western Coast. Cns Haniko Montgomery has been with us all morning long from Tokyo. Derek Van Damme is at the CNN Weather Center. Haniko, let's start with you there. Give us a sense of the latest of what you're hearing.

Yeah, of course. So as we know, the tsunami warnings have been downgraded to an advisory. But of course, we're still seeing lots of aftershocks from this very powerful earthquake. We've seen dozens of them, and people are still not allowed to return to their homes. The tsunami warnings haven't been entirely lifted. This is because the Japanese government and authorities are very concerned about potential damage. We know that hundreds of police officers, about 1,700 firefighters, 1,000 self-defense force personnel have been dispatched to this area in order to try to evacuate people to get them to safer places. Of course, when the earthquake happened at 4:10 PM local time, people were expected to drop their things and evacuate immediately to higher ground. But we're hearing reports of people trapped under their houses, so unable to get out, really. And of course, the military personnel are there in order to try to help people to safety.

And Derrick, let me bring you in here. We know, as John just said, that those tsunami warnings were just removed. What more can you share with us about that?

Well, they're still at play and they're still a threat of tsunamies. According to the Japan meteorological agency, that shading of yellow on the west facing shoreline of Japan all the way northward to Hikado has an advisory that's for up to one meter waves or roughly three and a half feet potential. And the reason for this is because we're getting this sloshing effect. Remember, we had a powerful 7.5 magnitude earthquake occur under the seafloor, and that caused a wave to propagate in all directions, not only regionally westward towards the Korean Peninsula and towards Russia, but also locally within the Ishiikawa prefecture, where we have seen some of the tsunami waves visible on the latest video. Look at it, crashing over the harbor wall that protects this city from such waves, right? This is Tudu City, and we're going to show you a hyper local detail of why this is important and give you an idea of what this sloshing effect is like. It's like throwing a stone into your bathtub, for instance, and watching the waves ripple back and forth from the edges back into the center, creating that chaotic wave type feature. Look at this.

This is a Google Earth map, and you can see the epicenter of the earthquake was just off of that little peninsula. That's the Ishi Kiawa prefecture. But we zoom in and Suzo City, where you saw the video just a moment ago, is on the opposite side of where the earthquake actually took place. So that sloshing effect is happening locally as well, bouncing off of the coastline as to my south and east. There's the harbor wall that it was breaking over. There's the population densities and the videos that we've seen really just confirming the narrative out of this area that's getting tougher and tougher to get communication because lines are down. But we have seen these waves up to about four feet in some locations. Remember, this powerful of an earthquake displaces the ground underneath where the tectonic plates actually meet. They are moving roughly about the same distance as your fingernails grow in the course of a year, roughly 80-90 millimeters, that's enough for seismic activity to be on the increase across this region. Guess what? As it happens under the ocean, it displaces that water, creates a wave up top. Then as it reaches the coastline where the population density is actually that wave goes up and up and up.

And that is why we have this fear of a tsunami, which, of course, is easing, but there is still the threat.

Still threat. Still be on alert there because they are warning that waves could reach four feet and depending where you are, that could create some problems. Derek Van Damme or thanks to you, Haniko Montgomery or thanks to you, has been with us all morning long from Tokyo. Just a short time ago, I spoke with an earthquake expert at Georgia Tech, and I asked him what damage this earthquake could cause.

Because of the event of this size that we expect a lot of offshocks. As you probably know, houses in Japan are relatively strong, they're mostly wooden building structures, so they can withstand some of the shaking, but if you have continuous vibration, mostly offshocks, then that could cause some damages. As you've already pointed out that sometimes if they cause fires, that could become another problem. Those are primary two things that I think people in the Central Region really have to watch out.

Yeah, again, and I can show people some of the video of the various shaking and damage. This was an island off the Coast here. You can see the roads there are damaged and cracked. This obviously makes it difficult to get aid and to get rescue operations underway if they're in any way needed. Obviously, there is more shaking and whatnot in other places as well. I'm glad you brought up after because I think in some ways the very term diminishes the threat. These are earthquakes. They may not be as powerful as the initial earthquake, but the repetition in and of itself can be very dangerous. Can you explain that?

Absolutely. One of the things that we know, like you pointed out, is typically people think that off-track is smaller than the main event, but there's always a very small percentage. We're talking about maybe like 5 or 10 % chance that an off track could be larger than the initial event. In that case, of course, we call the off track as the main event, and we call the previous event as the main shock. Things like this could happen, but it's a very small probability, but it's not zero. That's one thing I'd like to point out to your audiences, is that the sequence is still unfolding. It's not over yet.

Again, we're going to continue to fall developments from Japan. It is the middle of the night there. There is concern that people could be trapped in the rubble of the buildings, even as the tsunami warnings themselves are downgraded. So stay with us for much more information about all this as it comes in.