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“WHY IS L. A. TICKING?” INTRODUCTION & DEFINITIONS
“ WHY IS LOS ANGELES TICKING?”
IT’S ALL OUR FAULT, BUT IT’S
O. K.!
Ó Peter V. Boyd 1997/2011
702-423-6520
This is a revision, consolidation and update of three papers written after the 1994 Northridge Earthquake with additions made after May 2011 and the 8.7 Indonesian and 9.0 Chilean and Japanese quakes and Tsunami. Updated June 1st 2011.
The approach may be a bit circuitous, like the relationship of hidden faultlines, but the focus is always there, beneath the surface. Beneath Los Angeles .
* “It’s all our Fault, but it’s Alright!” about the types of faultlines in Southern California.
* “Southern California Chronology 1000 AD – 1993 AD ” About the physical and societal chronology of the state, with emphasis on the Los Angeles area. In this paper only some of the geologic elements are included.
* “Why is Los Angeles Ticking” About the perils of poor building design and construction, the lack of adequate brush clearance in our fire prone environment and some of the other areas that could lead to social and economic disaster.
Seeing the experience of the Japanese trifecta of earthquake, tsunami and nuclear disaster, the likelihood of Los Angeles’ level of peril is highly elevated.
Much of this was written in 1996 but it has been consolidated, revised and updated because nothing has changed, only that much more information is available and that certain theories have been proven correct.
The 2011 Earthquake and Tsunami in Japan only emphasizes the same points as they apply to the west coast of the United States . It only underscores the same principals and problems that existed then and, without any clear corrective measures, are even more perilous today.
The largest recorded earthquake in the United States struck Prince William Sound in Alaska on March 28th, 1964 , It was on Good Friday. Its magnitude was 9.2.
That’s 20 times as strong as the 2011 Japan quake.
Each year Southern California has around 10,000 earthquakes. Only a few hundred are over 3.0 and 15 to 20 are over 4.o.
On September 9th, 2001, there was a 4.2 magnitude centered in West Hollywood.
On March 16th 2010, there was a 4.4 magnitude centered in Pico-Rivera, three miles SSW of Whittier Narrows. Both earthquakes, though small, are in trigger zones for more seismic activity.
LET’S START WITH SOME DEFINITIONS
Words like: Magnitude. Richter Scale. Mercalli Scale. Momentary Magnitude. Focus. Epicenter and a few others that will pop up, so to speak, like Blind Thrust Fault. Slip Fault. Tectonic Plates. Subduction Zones, etc.
Some will appear in new sections, with explanation.
Much of the use of the term “Richter Scale” is a way of placating the public’s and the journalists’ desire to put labels on complex phenomena.
In the 1930’s the Japanese were in the lead in earthquake research, partly due to the trauma of the 1923 Tokyo quake. At that time Seismologist KiyooWadati publicized a method that assigned numbers to the magnitude of shockwaves using a system of monitoring sensing station’s readings and factoring them by the distance from the event. This produced communicable numbers to describe the event.
In 1935 Richter adapted Wadati’s work to a simple numeric scale that was in some ways based on the stellar scales that were in use by astronomers at Cal Tech at that time. He gave it a logarithmic scale to the power of 10, also an adaptation from astronomy, and with several revisions for distance and other variables, it provided communicable concepts to a mass audience.
“(Richter) introduced it (the scale) because he was tired of the newsman asking him about the relative size of earthquakes.” says seismologist Bruce Bolt of Cal Berkeley.
In the 1970’s, Hiroo Kanimori, a successor to Richter at Cal Tech, and a team of others, devised a far more complex and accurate system of scales that describe the event.
MESUREMENT OF EARTHQUAKE OBSERVATIONS - SINCE 1900
DISCRIPTOR MAGNITUDE ANNUAL AVERAGE:
GREAT : 8 AND HIGHER. 1 event was claimed in 1994, (Although now over four events have occurred between 1970 and 2011 in Chile, Alaska and Japan.)
MAJOR : 7 - 7.9 18 events.
STRONG: 6 - 6.9. 120 events.
MODERATE: 5 - 5.9. 800 events.
LIGHT: 4 - 4.9. 6,200 estimated events.
MINOR: 3 - 3.9. 49,000 estimated events.
VERY MINOR: Less than 2 - 2.9. 1,000 estimated events per day.
MAGNATUDE 1.0 – 1.9: 8,000 estimated events per day.
QUAKES AND THEIR MAGNITUDE –ENERGY RELEASE EQUIVALENT IN MILLIONS OF ERGS
