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Re: California Earthquake Problems

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Dear Yank

I want you to know my house was originally constructed in the 1950's
and thus has survived many vey high richter scale magnitude
earthquakes.  It survived the Alaska earthquake which I think was
magnitude 9.2.  It survived the whittier Narrows,Northridge, Sylmar
and Loma Prieta earthquakes.

Of course my house is in the South bay area of Southern California.

Maybe richter scale magnitude isn't very relavent.

Ken Tarlow


---Yank2002(--nospam--at) wrote:
> For those who are interested in the subject matter it is suggested
that this
> five-page (plus) long document be printed out for easier reading. 
> January 1999
> California Earthquake Problems  
> All structures built in California since 1933, including residential
> are built (or are supposed to be built) to comply with seismic code
> requirements so they do not collapse, or partially collapse, under
> forces generated by an earthquake. However, since seismic code
> are not, in any way, connected or linked to the
Richter-magnitude-scale, it is
> often problematic (if not impossible) to determine the equivalent of
> magnitude that a structure built according to the code can
> resist.
> Before we come to the central objective of this disclosure, we have
to point
> to certain historical events of the past 60 years which have led to
> distortions and misrepresentations made by the State of California
> These distortions continue to be duly disseminated and enforced;
still today,
> they are coerced on structural engineers to be administered and
> The seismic code for the State of California was an administrative
response of
> the state officials to the Long Beach earthquake of 1933 to prevent
a future
> possibility of children being crushed to death by collapsing school
> while attending classes. Since, at that time, "Richter magnitude
scale" was
> just introduced into the world of academia, the seismic code was
developed on
> some empirical data which, for obvious reasons, had nothing to do
with the
> "magnitude of an earthquake" as we know it today. 
> The seismic code of 1933 was "refined" every so often to stay "in
touch" with
> changes of the modern world. These changes, additions, or adjustments,
> however, had no connection whatsoever with the "magnitude of an
> subject matter. They were, at best, hypothetical attempts to fix or to
> "advance" code contingencies that were established initially on
> and untested assumptions. Moreover, the "refinements" of the most
current and
> any previous seismic code edition do not use, contain nor mention the
> generally accepted and recognized phrase "magnitude of an
earthquake", even
> for comparison purposes. "The earthquake magnitude" as a term does
not exist
> for structural engineers. The continued patch-up work on the
original seismic
> code and its empirical adjustments is the game the California state
> headed by the California Seismic Safety Commission and
change-resisting group
> of influential structural engineers, are still playing today without
a regard
> to what seismologists in the U.S. and all around the world are
> When asked by the property owner "what Richter scale magnitude my
> can withstand", most structural engineers are reluctant to respond
> this question, in fact, cannot be answered. As one of the prominent
> debating potential changes in seismic code requirements said on the
> engineering discussion group, "This issue should be important to
> engineers. If we just design per code as if it was a cook book, we
are going
> to make mistakes. We should at least try to understand the intent of
> code".  Another statement by a structural engineer was: "From my
standpoint, I
> would like to hear now how this information is given to the general
public so
> they better understand what it means when they are told their
building *is in
> conformance with the code*. Many of my projects relate directly to
> concept. When the firm evaluates a building and tells the owner they
> expect a 25% to 30% loss from a design based earthquake, they
obviously get
> concerned.  Many will say, "but the building was built to code!". 
> Still another comment was: .. In my opinion, far too many rash and
> overreactive code detail remedies have been promulgated, almost at
> fashion ...... But is it hardly unprecedented.  .. Unlike in the
> where defeated commanders are replaced with unimpaired once, after
> the same officials who allowed the failed buildings to be built
oversaw a
> great patchwork of remedial code changes. No reflection on the
integrity of
> those officials, but I think all those code changes should be
regarded as
> temporary, and replaced by simpler and more coherent once formulated
from a
> distance and free from control by those having personal
responsibility at the
> time of disaster. Code needs a fresh, dispassionate remake,
hopefully not (as
> before) understating the earthquake shaking or overstating material
> performance in the as-built realities. And it needs to be brought
back within
> an ordinary engineer's ability to grasp and correctly follow". (Also
see Note
> 2).
> The conclusion that can be drawn from these three comments is that
it is
> astonishing that engineers licensed by the state of California,
whose job is
> to design safe structures to protect the public from natural
disasters, do not
> understand what they are doing. 
> Some structural engineers want to believe that if the structure is
built "as-
> per-code", it should survive the earthquake without considerable
damage as
> long as its "magnitude" does not exceed the "acceptable level of
risk" - an
> official designation by the California Department of Conservation
(also see
> Note 1). The problem is that the "acceptable level of risk" is a
quantity that
> cannot be measured. In order to respond to the inquiring client in
such a way
> that he understands what to expect when an earthquake occurs, the
> level of risk" phrase is often translated (in an unofficial form,
i.e., behind
> the closed doors) to Richter scale magnitude of 6.6 or thereabouts.
Such a
> translation, however, is nothing more than an estimated guess
without a
> scientific, mathematical or logical basis. 
> The definition of the phrase has been questioned by seismologists
and many
> open-minded structural engineers when the analysis of earthquakes'
> aftereffects has shown that the term, "acceptable level of risk", as
> by the code, is a meaningless concept. The sad part of the story is
that, by
> law, engineers designing structures must comply with construction
> provisions of the seismic code which, theoretically and practically,
> nothing to do with seismology based reality. The loss of human lives
> enormous damage to properties caused by recent
minor-fault-earthquakes are
> indisputable testimonials to the erroneous and reckless way the
> seismic "safety" code is written and enforced. 
> Furthermore, since the general public, by reading newspapers and
> television, knows very well what kind of damage can be expected when
(say) a
> 5.3 or 6.6 Richter-scale-magnitude earthquake occurs but has
absolutely no
> idea what kind of damage can result when "an acceptable level of risk"
> criteria, as required by the code, was used to design the structure,
it is
> reasonable to expect that the process of identifying seismic
resistance of
> structures should be convertible to Richter scale magnitude (or any
> generally recognized meaningful scale system). The
> number-designated earthquake is understood by most humans living on
> planet; "an acceptable level of
risk"-compliant-structure-designation is not
> understood even by structural engineers. 
> You might want to say here that all this could be true, but you are
> concerned about what the State or the Universities are saying or
doing because
> any damage to your property is covered by an earthquake insurance
> Unfortunately this presumption is no longer valid today because of
the way the
> earthquake insurance policies are now written. After the Northridge
> earthquake, most insurance companies stopped selling new homeowners'
> which would have to include seismic coverage. Some insurers considered
> dropping their existing customers to reduce their exposure to
> losses. The state of California got into the picture and twisted an
arm here
> and pulled a leg there and as a result most insurance companies are
> required to offer earthquake insurance, but not on terms and
> resembling the pre-Northridge situation. Since the subject matter
> rather complicated requiring producing a lengthy report to be able
to see the
> true and untainted picture of the insurance aftereffects of the
> earthquake, we have to shorten it by making the following comparison:
> 1. The 1994 Northridge earthquake. Richter magnitude 6.7. Total
damage: $32
> billion. The amounts paid out by the insurance companies was a
record of $12.5
> billion. Several insurance companies became insolvent but were
rescued by
> state and federal governments so they wouldn't go bankrupt if all
> claims were to be paid. Hundreds of property owners with small or no
> earthquake insurance policies walked away from their homes, unable
to pay for
> the repairs..   
> 2. The Next San Andreas Fault Earthquake. Richter magnitude 7.3 -
8.0. The
> seismic energy release is anticipated to be 20-50 times more
powerful than the
> Northridge earthquake. According to seismologists, the most probable
> of the earthquake is expected to be one of the two high density
> areas along the fault. Total damage is estimated to be in the
vicinity of $170
> to $225 billion. The insurance companies say that if such damage
> occurs, they are incapable of paying out most of the earthquake
claims. Since
> state and federal governments are unable to rescue insurance
companies at this
> financial immensity level, thousands of property owners will have to
walk away
> from their properties as, by law, they cannot occupy red-tagged
> In view of the huge Northridge disaster and its affects on the
> companies, the state of California recently created California
> Authority (CEA), a system which, they say, will work for anticipated
> earthquakes. CEA is setting new rates and coverage limits for
> areas which, according to experts, translate into lesser coverage
and higher
> deductibles (L.A.Times, Dec 31, 1998). It would mean that, even for a
> "reasonable magnitude earthquake", only certain percentage of damage
> covered by the insurance policy. The rest has to come from the
> owner's pocket. In addition, the insurance policy will pay only for
> damages up to a certain maximum amount after deductibles are
> Damages to the interior, exterior, and other non-structural
components of the
> property including pools, patios, fences, driveways and detached
garages are
> not covered. An "extra-insurance" above the state established
insurance limit
> can be obtained from insurance companies which do not participate in
the CEA
> program --- at a prohibitive cost. In effect, a great majority of
> owners will be financially unable to repair structures that are not
> to withstand the maximum (M6.8 - M7.0) "non-San-Andreas-fault-
earthquake" or
> a medium (M7.2 - M7.6) "San Andreas fault earthquake" (see page 4 for
> explanation).
> A "Residential Earthquake Recovery" study conducted in 1996 by the
> of California at Berkeley points out that "even though scientists are
> confident that another disaster of the same (or similar) magnitude
as the
> Northridge earthquake will occur in a reasonable future, we cannot
expect that
> private insurers or federal agencies will be willing or able to
> victims with a comparable level of rebuilding assistance". The study
> points out that "a major seismic event is expected to take place
during the
> lifetimes of many of the current residents of California ... as the
last event
> took place in 1857 for Southern California and in 1906 for Northern
> California". 
> Below is an abbreviated information about earthquakes that, in the
past 25
> years, have affected the lives of people and also affected physical
> of properties in locations between the town of Mendocino (Northern
> and the Mexican border.
> The 1971 San Fernando (near Los Angeles) earthquake. A non-San
Andreas fault
> quake. Magnitude 6.5. Epicenter located in a medium density
population area.
> Death toll 65. Several major Interstate Highway bridges collapsed. A
> modern hospital destroyed requiring the rebuilding of the facility
> Hundreds of residential and commercial structures totally or partially
> destroyed. 
> The 1989 Loma Prieta earthquake. Magnitude 7.1. A San Andreas fault
> Epicenter located 35-45 miles away from high density population
areas. Death
> toll 62. Major highway bridges and overpasses 43 miles away from the
> (San Francisco Bay area) totally and partially collapsed. Hundreds of
> important commercial and residential structures totally or partially
> destroyed. Physical damage about $15 billion. 
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