New Tsunami

[bostonlass]

I just heard that an earthquake ranking 8.2 on the richter scale hit in the same place as the last one which caused the big tsunami in Sri Lanka. I have a question, but first I want to say that my thoughts and prayers go out to all of the people who are and might be affected by this one and by the last one and I hope everyone can be safely evacuated this time.

 

My question is, wouldn't the effects of this earthquake be felt in every ocean and not just the Indian ocean?

[mj from katy]

Bostonlass:

I just saw the reports, too. Like you, I hope and pray for the folks over there.

 

My DH could give you a really good answer since he's an ocean engineer, but I'll take a stab at it. I believe tsunamis form when the energy from the earthquake ripples through the water. When those ripples start encountering shallower water, that's when the tsunami builds and then breaks. The longer the wave has to dissapate, the less of a force it will be. That's why there was tremendous damage in Banda Aceh which was at the epicenter. And I saw reports from Thailand and Sri Lanka that there were sections of the beach that weren't that devastated, yet may have been only 1000 feet away from where the wave hit.

[boatbunny]

Hi Bostonlass,

 

Just heard the same thing myself, although they are not confirming there is actually a tsunami, it would be expected given an earthquake of this magnitude.

 

From what I read with the previous tsunami, yes, all of the oceans would be affected. However, the affect is marginal, there were actually 3 or 4 waves measured on the Cape (Cod) resulting from the tsunami that were above the size of the waves being experienced that day. But, they were only a few inches higher.

 

For those ships on the ocean, they basically feel a large swell under them as opposed to seeing a massive tidal wave coming at them. As the wave gets closer to land, obviously there is less water, so the wave actually starts building it's height at that point. Even boats that were out to sea only a couple of miles from land, didn't know that the tsunami had hit, they only felt a few minor swells under their boat. When they came in to shore, that's when they discovered the devastation. And those boats closer to the shore were affected after the waves hit land and the water rushed back out to the sea.

 

Luckily they are reporting now that thousands have moved to higher ground as soon as they felt today's quake. Last time I read that many people actually came to the shoreline to see the strange phenomenon of the tide moving out so quickly, as we now know is a classic warning sign that a tsunami is about to hit. There had not been a tsunami in that region for so long that the natives did not realize that the tide going out was their warning to move.

 

I agree, saying an extra prayer right now for the people who have already been so devastated this year. I have been sorting clothes and toys for a trip to Goodwill, I think I will find out if these items might be needed for this area instead.

[bostonlass]

It's so strange because just yesterday coming home from Easter dinner, I was looking at the ocean (we live right on it) and the waves looked awefully big and rougher than normal. That's exactly how they were a few weeks after the tsunami hit as well. I also remember reading a LOT of reviews with people saying they have rough seas on their cruises, though I'm not sure if Dec/Jan is a particularly rough sea time or not.

[Globaliser]

My question is, wouldn't the effects of this earthquake be felt in every ocean and not just the Indian ocean?

The effects of the Boxing Day tsunami were "felt" in pretty much every ocean - but once you got a reasonable way away from the Indian Ocean you would have to have been a specialist, or to have had specialist measuring equipment, to detect it.

 

Yesterday's earthquake is said to have triggered a small tsunami - detected at about 10 cm at the Cocos Islands. That's the sort of level which you probably wouldn't notice if you were just standing on the beach.