Sunday, November 21, 2010

Re: [californiadisasters] Re: Very interesting website. My own Earthquake experiences. Yahoo Groups.



Achtung Herr James!

I was reminded by some of my excellent moderators that a few clarifications to your posting are due.

First off, California Disasters neither encourage nor discourage its members from signing up to your website and taking your poll. The prerogative and discretion for that rests entirely in the hands of the individual member.

Secondly, I remind you that the phase of the moon has no scientific relevance to the timing of earthquakes which are caused by plate tectonics which are driven by the Earth's internal heat engine. Those whom dispute this bare the burden of scientific proof and thus far none have been able to bare that burden successfully since the acceptance of Plate Tectonics Theory.

Lastly, which direction a quake breaks along a fault plane does not make it more or less severe other than the "directivity" of the seismic energy.

In general quakes that rupture along fault planes out of the north towards the south are not any worse than otherwise.

There is one caveat to this, however, and that is that if in the direction in which the quake is propagating down a fault plane there exist communities of human beings and/or their constructs then they will experience greater ground acceleration that otherwise.

In an earthquake a community nearby but north of a section of fault plane breaking from north to south will not receive nearly as much seismic energy as a community nearby but south of a section of fault plane breaking from north to south. Does that make sense?

The City of San Francisco was essentially the epicenter of the 1906 Great Northern California Earthquake (actually, the epicenter was near the Golden Gate back before there was a bridge there) and received a surprisingly limited amount of damage from the earthquake itself given the building materials and structural designs of the period. This is due to directivity as the San Andreas Fault Zone broke bilaterally AWAY from The City north and south during the earthquake. 

Both the Landers event in 1992 and the Hector Mines/Lavic Lake event of 1999 BOTH broke from SOUTH to NORTH which sent the bulk of their seismic energy into the public lands and military bases of the Mojave Desert and away from more populated areas to the south of the sections of faults that broke in both events.

The Northridge event of 1994 actually had a hypocenter beneath Reseda directly beneath the intersection of Reseda Blvd. and Saticoy Street although most of the energy of the quake was directed into the northern San Fernando Valley and the Santa Susana Mountains to the north which were jacked up a foot or more. The reason for this directivity is due to the fact the quake broke from depth upwards along a south-dipping Northridge Thrust Fault Zone (a.k.a. Pico Thrust F.Z.) and thus as the seismic waves piled up as they rose they were directed towards the north at an oblique angle away from the epicenter in the southern San Fernando Valley.

The San Simeon Earthquake of 2003 was epicentered nearly beneath Hearst Castle which received light damage as rupture of the Oceanic Fault Zone propagated southeastward AWAY from Hearst Castle and towards Paso Robles/Templeton/Atascadero which three communities received the most damage but were much further away from the section of fault that ruptured. That is due to "directivity".

If any of this needs further clarification please let me know and I'd be glad to perhaps better elaborate.

Another great group we promote here and is a second sister group to this one after Californiasearthquake zone is Geology2:

http://tech.groups.yahoo.com/group/geology2/


Kim Patrick Noyes




On Sat, Nov 20, 2010 at 8:07 PM, Kim Patrick Noyes <kimnoyes@gmail.com> wrote:
 

James,

Welcome to CD and thanks for your input which is welcome as is relevant disaster-related input from the rest of our members.

I invite you to join Californiasearthquakeforum group as well.

http://tech.groups.yahoo.com/group/californiasearthquakeforum/

Kimmer



--- In californiadisasters@yahoogroups.com, "james362001" <james362001@...> wrote:
>
> Now this is what I call an original Yahoo Group. I live in an Earthquake area where the San Andreas Fault cuts thru the Antelope Valley Freeway. The newspapers have really been hyping it up that we are overdue for The Big One. They believe that the San Andreas wakes up with a very dangerous shake on the average 150 years, from Parkfield to Los Angeles. It is now past this mark. I have lived through many Earthquakes in my life. My first being the San Fernando Earthquake on February 9, 1971. It was a Tuesday, no moon, 6:01am. Richter scale: 6.7.
> Even more dangerous are the ones that come from the north. I'm not sure if it was the Landers quake, but this particular one was a "thrust". Instead of shaking west to east as it seems, it lifted up and down. It was so violent. It literally was enough to make you fall out of bed. It put me down on the ground so hard when I stood up.
> Dispite my own life experiences, one of my favorite disaster movies is Earthquake (1974).
>
> Just thought I would like to share a few sites.
>
> I have created a poll on Rate It All for those that would like to vote for the worst California Earthquake they have ever been through or heard of. The list ranges from 1933 to 2010. I will be adding the 1906 Earthquake soon, just for historical sake.
> The poll is called "California Earthquakes" and I do update it when a new quake strikes and it is significant.
> You will have to register for free on "Rate it All" to get to the poll.
> http://www.rateitall.com/topic.aspx?topicid=3014091&sename=california-earthquakes
>
> For those that are interested in the California High Speed Rail, the California-Nevada Maglev Super Speed Train or DesertXpress, I have a Yahoo group that will update you on construction dates.
>
> http://groups.yahoo.com/group/CaliforniaSpeedTrains
>
> also on my group is a link that will take you to the USGS Earthquake Map so you can see where an earthquake has happened in the state andin your area recently.
>
> Thank you for your Group. I will have fun looking around.
>





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