eearthuake

[mikester]

I'm a few miles from the epicenter - it was quite a roller. Scared the heck out of the wife and I. It was over quickly, 4.5 year old slept through it. I think I woke up the baby checking on him.

[tabs]

As stated previouslily a rule of thumb...The more the Jolt the closer you are to the epicenter, the more the ROLL the farther away. When I lived in Upland had an epicenter about a 1/4 to 1/2 mile away..all I heard was a big bang and a jolt... and the dogs tail sticking out of the ground.

[Danimal16]

Originally Posted by varmint

must have been significant. my building is on solid rock. and i still felt it. lasted a good ten seconds.

You will feel the earthquake on solid rock more so than on alluvium. The beauty is that the rock allows the shock wave to travel at high speed and low amplitude. On the other hand, alluvium slows the wave down resulting in significant increase in amplitude and that is where the bad ju-ju starts.

[Danimal16]

Originally Posted by 450knotOffice

Down here in south OC, the quake started as a really subtle little shake (I wondered for a couple of seconds if one of my dogs was bumping up against the couch), then picked up in intensity for a few seconds, and then it was done. The whole event lasted maybe 8 to 10 seconds.

Todd is right. I've felt much stronger quakes. Much stronger. This was nothing.

Don't you hate the anticipation of if it is going to continue, or like in 71 when it started, kept going and than really started to shake the heck out of everything?

Didn't feel it here in Moorpark.

[Danimal16]

And to think the 64 Alaska Quake shook for 4-5 minutes.

The strong ground motion reported in the Anchorage area lasted about 4-5 minutes which triggered many avalanches and landslides - some being tsunamigenic. Ground deformations were extensive with some areas east of Kodiak being raised by 30 feet and areas about Portage being dropped by 8 feet (Pflaker, 1964). The rise is estimated to come in two thrusts of about 5 meters each. The maximum intensity reported was XI on the modified Mercalli Intensity scale, indicating major structural damage, and ground fissures and failures. This scale is a 12-point one usually given in roman numerals ranging from I, (not felt/no damage) to XII (total destruction many lives lost). From this event, significant damage covered an area of about 50,000 square miles. Intensities of IV-V (felt by most people/minor damage) were reported as far away as Cold Bay, Bethel, McGrath, Kotzebue, Deadhorse, Ft. Yukon, Eagle and Skagway.

[onewhippedpuppy]

Originally Posted by ckissick

Apparently, the size of an earthquake is directly proportional to how badly one spells "earthquake" immediately after the event.

I figured he was still shaking.

Get the big one out of the way, would ya? I have to come back there in a few weeks.

[mikester]

Originally Posted by tabs

As stated previouslily a rule of thumb...The more the Jolt the closer you are to the epicenter, the more the ROLL the farther away. When I lived in Upland had an epicenter about a 1/4 to 1/2 mile away..all I heard was a big bang and a jolt... and the dogs tail sticking out of the ground.

Well, the epicenter was reported as Lennox and I'm in El Segundo.

barely a mile or two away but they did say it was deep, something like 8.4 miles underground.

[Zeke]

Originally Posted by nostatic

Some of you guys haven't been through a "biggie." That was a minor ripple

I was asleep during the first few seconds. When what the news called the "bang" occurred, I jumped up like a cat. All the cupboard doors and drawers were open and a few things fell down that probably should better secured. One framed picture fell and broke glass all over. We spent a half hour vacuuming broken glass.

Speaking of cats, I haven't seen mine yet this morning.

[red-beard]

I didn't feel it here...

[BeyGon]

Felt it pretty good here but I had been in Laguna all afternoon with friends for my birthday so at 8 I wasn't moving too fast. Didn't even get up off the couch. The Cliff makes good Mojitos. I think.

[ramonesfreak]

news reports it at 4.7
http://www.ktla.com/news/landing/ktla-5-earthquake-losangeles,0,293623.story

[450knotOffice]

Originally Posted by Danimal16

Don't you hate the anticipation of if it is going to continue, or like in 71 when it started, kept going and than really started to shake the heck out of everything?

That's usually the worst part. "Is this the beginning of a BIG one?" is what goes through mind when they start.

[dd74]

Originally Posted by Danimal16

You will feel the earthquake on solid rock more so than on alluvium. The beauty is that the rock allows the shock wave to travel at high speed and low amplitude. On the other hand, alluvium slows the wave down resulting in significant increase in amplitude and that is where the bad ju-ju starts.

I've heard this theory before. I was told that many houses in the Hollywood Hills are built on rock, and will best withstand a major earthquake. Anything near or on the coast, however, is as good as collapsed.

BTW: felt just a slight jolt and roll where I live.

[Danimal16]

Originally Posted by dd74

I've heard this theory before. I was told that many houses in the Hollywood Hills are built on rock, and will best withstand a major earthquake. Anything near or on the coast, however, is as good as collapsed.

BTW: felt just a slight jolt and roll where I live.

During the Northridge quake we saw the direct results of this on our water distribution system. The really old pipes over in the Santa Sussana hills had minimal damage if any. On the other side of the valley over by the Marr Ranch out in to Tapo Canyon, tons of broken pipes. Million gallon water tanks moved 15 inches snapping fittings. A lot was learned from that quake, like vertical accelerations CAN exceed one G.

[dd74]

Originally Posted by Danimal16

During the Northridge quake we saw the direct results of this on our water distribution system. The really old pipes over in the Santa Sussana hills had minimal damage if any. On the other side of the valley over by the Marr Ranch out in to Tapo Canyon, tons of broken pipes. Million gallon water tanks moved 15 inches snapping fittings. A lot was learned from that quake, like vertical accelerations CAN exceed one G.

Danimal - are you involved with geological operations or Caltech?

My mum-in-law used to have a house right below the Hollywood Sign. A couple shakers shook that place hard, but it was very solid - almost jarring. I would think down in Santa Monica, the same type of shaking would have the house slipping off their foundation.

[Danimal16]

Originally Posted by dd74

Danimal - are you involved with geological operations or Caltech?

My mum-in-law used to have a house right below the Hollywood Sign. A couple shakers shook that place hard, but it was very solid - almost jarring. I would think down in Santa Monica, the same type of shaking would have the house slipping off their foundation.

No, not that smart. But did alot of seismic retrofits. There are some folks on this board though that know the region better than I do. I concentrated on the formations in Simi Valley. We did have some large slabs slide into a farm back along the Mine Road area, at the end of Tapo Canyon. I just had an interest in lifeline engineering as it related to the water systems. Specifically to assure adequate water supply to prevent what is called a "fire following" event. See the great San Francisco earthquake on how devastating one of those deals can be. Also, it was the fires that did the killing in the Hashin (Kobe) quake. The dead were trapped in their collapsed tile roof homes and burned to death. Gruesome stuff.

[dd74]

That's what I worry about - the fire and gas explosions - after a quake. The (in my case) DWP infrastructure is what I worry about next.

Aren't there house gas meters now that shut off automatically if there's been a large quake?

To be honest, all this worry makes me want to get a good-sized Catepillar diesel generator.

[Zeke]

Originally Posted by dd74

That's what I worry about - the fire and gas explosions - after a quake. The (in my case) DWP infrastructure is what I worry about next.

Aren't there house gas meters now that shut off automatically if there's been a large quake?

To be honest, all this worry makes me want to get a good-sized Catepillar diesel generator.

Yes, there are valves that allow a ball to fall off a perch and seal the gas line from the meter on in to the house. They don't cost a lot, but do require some piping to get them installed. A plumber with a nipple rack and some L's could do it in 30 minutes.

[Jim Bremner]

nipple rack

[Danimal16]

One of the big things will be fire fighting water. Each city uses different standards. This has to do with the water in the steel tanks or other reservoirs, not the capacity at the house or the hydrant. Fire Marshals will argue that all day long but if those reservoirs fail, there ain't no water.

There are a number of factors that deal with the amount of the water that needs to be stored based on density, construction type, use and the standards that the community chooses to utilize. The last item is a real bone of contention with developers. A lot of folks do not understand just how undersized their systems are and how important it is to make the construction of storage and transmission capacity a part of the development. If the developer pays a share of a fee to a fund, you are behind the cost curve and nearly certain to have an undersized system as soon as that development comes on line. The best examples of that, and there are many in California, are the Oakland fire, Laguna Beach, Malibu (the city portion), the recent fires in Orange County where the lack of storage was the main culprit. This was also the case in the great San Francisco earthquake as well.

The other issue with developers paying into a fund is the fact that construction material and labor costs ALWAYS exceed the amount earned on a fund. The other issue is that unknown to the public is these utility reserves are easy targets for politicians to redirect to their pet projects. There are tons of examples of that one.

I could go on for days on this. In Simi we did not use the state standards. They, even though recently updated, are IMHO grossly inadequate for the typical modern day (pack em in tight) development. Just for comparison the Simi Standard (and many other well run utilities/cities use the same) for single family residential was 1500 gpm for 4 hours duration, that is each pressure or isolated zone, by GRAVITY, must have at least 180,000 gallons of fire storage. The state calls for 500 at 2 hours. This is in addition to the other storage components including O&M, Municipal and Industrial, etc.

And it is further complicated by the common practice of municipal leaders not insuring these standards are met favoring the developers profits over staff's enforcement of the standards.

I have seen this change dramatically in the past decade and the results are becoming apparent. Not just in water but in the reserves that have been squandered by pandering politicians at all levels to promote their self serving give away programs that yield nothing. And people wonder why utility rates are going up so much. One factor is it is pay back time for those petty politicians that got what they wanted and are now long gone.