Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Ok OP. Here's a question.

In 2007(or 8) to took the Ca bar at the Ontario
Convention center 40 miles east of LA. In the middle of the exam there was a quake. The epicenter was Ontario. Sounded like a bomb going off. Shook the chandeliers. No broken windows. Over in a flash. The panic was the problem. But it wasn't that disturbing.

My exwife was sitting for the bar at the San Diego convention center. Yet there it was felt as a much more significant earth movement. And there was damage. Windows and wall cracks but damage.

Why? SD is 100 miles at least from Ontario

The difference could be site effects. Ontario is inland; the San Diego convention center is on mud, which will amplify shaking. I assume the earthquake in question was 2008-07-29 18:42:15 UTC Chino Hills CA earthquake (11:42 AM PDT). This was much closer to Ontario. I wonder if I have the wrong date, though. From 2007-2009 there were only three M>4.5 earthquakes in So. CA, and only the Chino Hills earthquake occurred around when the bar was taken.

But, site effects and amplification is real. In 1985, a magnitude 8.0 earthquake hit the west coast of mexico. Damage was moderate in that region, but in mexico city, 300 east of the epicenter, the damage was severe. The lakebed that is mexico city shook like jello. That is a technical term. More accurately, the sediments amplified the energy and generated surface waves which were of large amplitude. Site effects.

That's the quake.

Anonymous wrote:

Anonymous wrote:Ok OP. Here's a question.

In 2007(or 8) to took the Ca bar at the Ontario
Convention center 40 miles east of LA. In the middle of the exam there was a quake. The epicenter was Ontario. Sounded like a bomb going off. Shook the chandeliers. No broken windows. Over in a flash. The panic was the problem. But it wasn't that disturbing.

My exwife was sitting for the bar at the San Diego convention center. Yet there it was felt as a much more significant earth movement. And there was damage. Windows and wall cracks but damage.

Why? SD is 100 miles at least from Ontario

The difference could be site effects. Ontario is inland; the San Diego convention center is on mud, which will amplify shaking. I assume the earthquake in question was 2008-07-29 18:42:15 UTC Chino Hills CA earthquake (11:42 AM PDT). This was much closer to Ontario. I wonder if I have the wrong date, though. From 2007-2009 there were only three M>4.5 earthquakes in So. CA, and only the Chino Hills earthquake occurred around when the bar was taken.

But, site effects and amplification is real. In 1985, a magnitude 8.0 earthquake hit the west coast of mexico. Damage was moderate in that region, but in mexico city, 300 east of the epicenter, the damage was severe. The lakebed that is mexico city shook like jello. That is a technical term. More accurately, the sediments amplified the energy and generated surface waves which were of large amplitude. Site effects.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:My DH has felt tremors from 5 earthquakes. What are the chances of that?

Even in Northern VA, I felt shaking from 7 earthquakes since I lived hear. It is not surprising.

DH and I both grew up in Ohio, went to college Boston and have lived in Bethesda together for 20 years. Yet he's experienced 5 more earthquake tremors than me. Seem odd to me.

The "obvious" answer is that he's an earthquake magnet. You should divorce him. He'll only bring you destruction.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:My DH has felt tremors from 5 earthquakes. What are the chances of that?

Even in Northern VA, I felt shaking from 7 earthquakes since I lived hear. It is not surprising.

DH and I both grew up in Ohio, went to college Boston and have lived in Bethesda together for 20 years. Yet he's experienced 5 more earthquake tremors than me. Seem odd to me.

Anonymous wrote:Ok OP. Here's a question.

In 2007(or 8) to took the Ca bar at the Ontario
Convention center 40 miles east of LA. In the middle of the exam there was a quake. The epicenter was Ontario. Sounded like a bomb going off. Shook the chandeliers. No broken windows. Over in a flash. The panic was the problem. But it wasn't that disturbing.

My exwife was sitting for the bar at the San Diego convention center. Yet there it was felt as a much more significant earth movement. And there was damage. Windows and wall cracks but damage.

Why? SD is 100 miles at least from Ontario

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:My DH has felt tremors from 5 earthquakes. What are the chances of that?

Even in Northern VA, I felt shaking from 7 earthquakes since I lived hear. It is not surprising.

DH and I both grew up in Ohio, went to college Boston and have lived in Bethesda together for 20 years. Yet he's experienced 5 more earthquake tremors than me. Seem odd to me.

Anonymous wrote:

Anonymous wrote:My DH has felt tremors from 5 earthquakes. What are the chances of that?

Even in Northern VA, I felt shaking from 7 earthquakes since I lived hear. It is not surprising.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Why not talk about the ones in Italy and Myanmar? I don't recall seeing two 6 plus earthquakes in separate parts of the world on the same day.

Because the author of this thread is a troll and doesn't know any technical info.

The author of this thread addressed this question earlier. Not sure where you get the idea that she doesn't know what she's talking about. If I asked a lawyer questions about their job, do you think they'd spit out Blue Book cites?

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Could the high death toll in Amatrice have been avoided today?

Possibly. 6.2 is not that big; earthquake resistant building, for example, would help. I have not really looked at anything related to that earthquake (I had medical tests the AM, and just finished that up).

A good way to look at this is to go to 2010. Two earthquakes, a 7.1 in Haiti, and an 8.8 in Chile occurred 6 weeks apart. The Chilean event was about 100x bigger than the Haiti earthquake, but had very few casualties. Why? Building codes. By comparison, the smaller Haitian earthquake hit in a poor city with no building codes; possibly over 200,000 people were killed. Building codes and code enforcement matter.

At least 75 people have died and entire towns have been leveled. How can you say 6.2 is not "big" in relation to the structures the quake is hitting. It may not be "big" compared to an 8.2, but a 6.2 can cause massive damage and kill people.

Amatrice is a very, very old city and has foundations and construction that reflect that. It was not designed or built to withstand a quake. Myanmar is a poor third world country and that's being generous. It was als not built to withstand an earthquake. Relatively speaking a 6.2 is not big. If it hit a big city, there would be some damage. But nothing catastrophic

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Why not talk about the ones in Italy and Myanmar? I don't recall seeing two 6 plus earthquakes in separate parts of the world on the same day.

Because the author of this thread is a troll and doesn't know any technical info.

The author of this thread addressed this question earlier. Not sure where you get the idea that she doesn't know what she's talking about. If I asked a lawyer questions about their job, do you think they'd spit out Blue Book cites?

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:How did you end up in seismology? What degrees do you have?

I was interested in it. BS in Geophysics, MA/PHD in Geological Sciences (but work was in geophysics)

What triggered your interest? Did you know going into undergrad? Have a class that sparked something?

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Could the high death toll in Amatrice have been avoided today?

Possibly. 6.2 is not that big; earthquake resistant building, for example, would help. I have not really looked at anything related to that earthquake (I had medical tests the AM, and just finished that up).

A good way to look at this is to go to 2010. Two earthquakes, a 7.1 in Haiti, and an 8.8 in Chile occurred 6 weeks apart. The Chilean event was about 100x bigger than the Haiti earthquake, but had very few casualties. Why? Building codes. By comparison, the smaller Haitian earthquake hit in a poor city with no building codes; possibly over 200,000 people were killed. Building codes and code enforcement matter.

At least 75 people have died and entire towns have been leveled. How can you say 6.2 is not "big" in relation to the structures the quake is hitting. It may not be "big" compared to an 8.2, but a 6.2 can cause massive damage and kill people.