PLEASE NOTE:
*
CCNet 34/2002 - 14 March 2002
-----------------------------
"Risk managers will have to think the unthinkable in the
future -
that is another thing the terrorist attack of 11th September 2001
in
the United States has shown - and they will have to consider
maximum
loss potentials that are albeit improbable but nevertheless
possible.
Accordingly Munich Re's scientists devote a section in the new
study to the
first in-depth investigation into the risk of meteorite crashes,
of which
around 100 were documented last century. These crashes are
capable
of causing a wide range of damaging effects. The study shows that
the
effects of a "bombardment from space" are to be carried
by the insurance
industry to a larger degree than has hitherto been assumed. This
is because
meteorite crashes will probably lead to explosions and numerous
fires,
which are covered in many insurance contracts nowadays."
--Munich Re, 13 March 2002
(1) FOUR YEARS AFTER 1997 XF11, JPL ANNOUNCES GREATLY IMPROVED
TOOL FOR
ASSESSING IMPACT RISK
Benny J Peiser < b.j.peiser@livjm.ac.uk
>
(2) SENTRY - AN AUTOMATED NEAR-EARTH ASTEROID COLLISION
MONITORING SYSTEM
Ron Baalke < baalke@jpl.nasa.gov
>
(3) IMPACT RISK ASSESSMENT: AN INTRODUCTION
http://neo.jpl.nasa.gov/risk/doc/sentry.html
(4) AFTER 9/11: IMPACT RISK UNDERESTIMATED, INSURANCE STUDY WARNS
Reiner M. Stoss, Starkenburg Observatory
(5) NATURAL CATASTROPHE BALANCE 2001
Munich Re, 13 March 2002
(6) AN ANCIENT ROCK RAIN IDENTIFIED
inScight, 12 March 2002
(7) DEADLINE APPROACHES FOR NEXT ROUND OF SHOEMAKER NEO GRANTS
Ron Baalke < baalke@jpl.nasa.gov
>
(8) "MARS EROSION FEATURES CARVED BY LIQUID CO2, NOT RUNNING
WATER"
Harvey Leifert < hleifert@agu.org
>
(9) SPACE WEAPONS, EARTH WARS: NATURAL METEOROIDES AS WEAPONS
James Perry < AJDPerry@aol.com
>
(10) C/2002 C1 (IKEYA-ZHANG)
Mark Kidger < mrk@ll.iac.es
>
================
(1) FOUR YEARS AFTER 1997 XF11, JPL ANNOUNCES GREATLY IMPROVED
TOOL FOR
ASSESSING IMPACT RISK
>From Benny J Peiser < b.j.peiser@livjm.ac.uk
>
On 12 March, exactly four years to the day after the first near
earth
asteroid, 1997 XF11, was announced to have a non-zero impact
probability,
NASA's Near-Earth Object Program Office launched their new SENTRY
automatic
impact monitoring system (see info below).
The new SENTRY system is another big improvement in the way the
NEO
community now routinely monitors and assesses potential (or
virtual) impact
events. I congratulate the JPL team behind the new programme and
wish them
all the best.
As CCNet readers are only too aware, the main problem with the
handling of
virtual impactors has been due to shortcomings in the way such
information
has been worded or publisised or both. In view of the new
automatic
monitoring system, I hope that we will also adapt future risk
communications
in accordance with lessons and experiences learnt from new
discoveries and
past mistakes.
We have come a long way since 1997 XF11 and have learned over the
last three
years that 'false alarms' are almost inevitable - just as they
occasionally
occur in other disaster warning systems. Yet little of this
progress would
have been made if the 1997 XF11 (and subsequent ateroid alarms)
had never
happened.
At the same time as SENTRY was launched, another asteroid with a
non-zero
impact probability was announced by the new programme. In fact,
2002 CU11 is
flagged up as a Torino Scale 1 object. However, since the
cumulative Palermo
scale for 2002 CU11 remains negative, JPL abided by the rules and
did not
request an IAU review.
2002 CU11 was discovered on 7 February and the observations
currently extend
to 10 March. The arc is currently quite good, though not as good
as 1997
XF11 and 1999 AN10 at the time of their Torino class 1-2 impact
possibilities in 2040 and 2044.
Both SENTRY and NEODys give an identical impact probability for
2002 CU11
(for 31 August 2049) of a 1 in 100,000 chance of impact.
Nevertheless, while JPL's SENTRY website
has flagged up 2002 CU11 as a Torino Scale 1 object, the NEODYs
RiskPage
does not mention this characteristic.
With SENTRY and the NEODys agreeing so well, there seems to be
little need
for the IAU "technical" review process. There seems to
be no reason to doubt
the accuracy of either the NEODys or SENTRY programmes. All that
is
required, as far as I can see, is an assessment of whether or not
any
official or public "statement" is warranted. At times,
it might be much
wiser simply to add some further explanations and clarifications
to the risk
pages so that the technical details of virtual impactors can be
properly
understood by the average reader.
With regard to JPL's new programme and website, I would find it
extremely
helpful if SENTRY could inform readers not only about the exact
time an
object is found to have a non-zero impact probability; equally
interesting
would be to know about future observational opportunities as well
- and thus
the likely time during which the risk, most likely, will
disappear). What is
more, by studying the chronological sequences and evolution of
temporary
virtual impactors we may - perhaps - even learn something of
interest.
Benny Peiser
=============
(2) SENTRY - AN AUTOMATED NEAR-EARTH ASTEROID COLLISION
MONITORING SYSTEM
>From Ron Baalke < baalke@jpl.nasa.gov
>
NASA's Near-Earth Object Program Office ( http://neo.jpl.nasa.gov )
announces
the arrival of the Sentry automatic impact monitoring system. In
development
for nearly two years, Sentry is a highly automated, accurate, and
robust
system for continually updating the orbits, future close Earth
approaches,
and Earth impact probabilities for all Near-Earth Asteroids
(NEAs).
When interpreting the Sentry Impact Risks Page
( http://neo.jpl.nasa.gov/risk/
), where information on known potential NEA
impacts is posted, one must bear in mind that an Earth collision
by a
sizable NEA is a very low probability event. Objects normally
appear on the
Risks Page because their orbits can bring them close to the
Earth's orbit
and the limited number of available observations do not yet allow
their
trajectories to be well-enough defined. In such cases, there may
be a wide
range of possible future paths that can be fit to the existing
observations,
sometimes including a few that can intersect the Earth.
Whenever a newly discovered NEA is posted on the Sentry Impact
Risks Page,
by far the most likely outcome is that the object will eventually
be removed
as new observations become available, the object's orbit is
improved, and
its future motion is more tightly constrained. As a result,
several new NEAs
each month may be listed on the Sentry Impact Risks page, only to
be removed
shortly afterwards. This is a normal process, completely
expected. The
removal of an object from the Impact Risks page does not indicate
that the
object's risk was evaluated mistakenly: the risk was real until
additional
observations showed that it was not.
While completely independent, the Sentry system is meant to be
complementary
to the NEODyS CLOMON impact monitoring system operated in Pisa,
Italy.
Personnel from both the Sentry and NEODyS systems are in constant
communication, cross checking each other's results and providing
constructive feedback to continuously improve the efficiency,
accuracy, and
robustness of both systems.
The Sentry system was developed largely by Drs. Steve Chesley and
Alan
Chamberlin with significant technical help from Dr. Paul Chodas.
Ron Baalke
provided our web site updates.
Donald K. Yeomans
Manager, NASA's Near-Earth Object Program Office
March 12, 2002
===============
(3) IMPACT RISK ASSESSMENT: AN INTRODUCTION
http://neo.jpl.nasa.gov/risk/doc/sentry.html
When interpreting the Sentry Impact Risk Page, where information
on known
potential NEA impacts is posted, one must continually bear in
mind that an
Earth collision by a sizable NEA is a very low probability event.
Objects
normally appear on the Risk Page because their orbits can bring
them close
to the Earth's orbit and the limited number of available
observations do not
yet allow their orbits to be well-defined. In such cases there is
a wide
variety of future orbits that can be fit to the existing
observations,
sometimes including a few that can intersect the Earth. Whenever
a recently
discovered NEA is posted to the Sentry Impact Risk Page, by far
the most
likely outcome is that the object will eventually be removed as
additional
observations are processed, the object's orbit is improved, and
its future
motions are more tightly constrained. As a result, NEAs will
routinely be
listed on, and removed from, the Sentry Impact Risk Page,
sometimes
appearing only briefly. This is a normal ongoing process -
completely
expected. Hence, the placement of objects upon the Impact Risk
Page and
their subsequent removal therefrom do not indicate that an object
was
mistakenly thought to be a risk. It was a risk - until additional
observations rendered it otherwise. On the other hand, the Impact
Risk Page
lists a number of lost objects that are, for all practical
purposes,
permanent residents of the Risk Page; their removal may depend
upon a
serendipitous rediscovery.
Most visitors to this web site will be primarily interested in
the table
presented on the Impact Risk Page. The rightmost two columns
quantify the
risk posed by the tabulated objects, using both the Torino Scale,
which was
designed primarily for public communication of impact risk, and
the Palermo
Technical Scale, which was designed for technical comparisons of
impact
risk. A Palermo Scale value less than zero and, in most cases, a
Torino
Scale value of zero, indicate a risk below the so-called
background level
(more info here), which is the average risk from the entire NEO
population.
To date, the risks posed by the potential impacts identified by
Sentry have
all been well below the background level, and hence, these events
have been
of academic or professional interest only, and not deserving of
great public
concern. Events with a Palermo Scale value greater than zero are
expected to
be very rare, but if one should be predicted, a Technical Review
of the
prediction would likely be requested from our colleagues in order
to verify
the calculations before the prediction is placed on the Risk
Page.
For each object listed on the main Risk Page there is a separate
page
providing more detailed technical information, some of which is
included
only to facilitate cross-checking among specialists involved in
computing
these predictions. The computation of Earth impact probabilities
for
near-Earth objects is a complex process requiring sophisticated
mathematical
techniques. An abbreviated and simplified explanation of the
entire
computation process is presented below and a Frequently Asked
Questions page
is available. For those who wish a more in depth mathematical
explanation of
this risk assessment process, please see the paper entitled
Asteroid Close
Approaches: Analysis and Potential Impact Detection by A. Milani,
S.R.
Chesley, P.W. Chodas, and G.B. Valsecchi (2002).
THE SENTRY AUTOMATIC ORBIT/CLOSE APPROACH UPDATE PROCESS
Every day, observations and orbit solutions for Near-Earth
Asteroids (NEAs)
are received from the Minor Planet Center (MPC) in Cambridge,
Massachusetts.
Once classified as an NEA, the asteroid is thereafter given
automatic orbit
updates within our Sentry system. A new orbit solution for an NEA
is
computed whenever new optical or radar observations for that
object become
available. Some high-priority objects are observed daily, while
other
objects go unobserved for days or weeks, even though they may
still be
bright enough to be seen. Optical observations cease when an
object recedes
from the Earth (becoming too faint to be seen even with
moderate-size
telescopes), or when the object moves into the daytime sky.
Similarly, radar
observations are possible only when the object is near enough to
the Earth
for the echo of a radar bounce to be detected. Once all the
observations for
an object have been collected, an orbit determination process is
used to
find the orbit which best fits all the observations.
The orbit is defined by six parameters (called the orbital
elements) at an
initial time (called the epoch). An object's orbit is constrained
to follow
equations of motion which model the forces expected to be acting
on that
object at any given time. These forces are primarily the
gravitational
attraction of the Sun, the planets, the Earth's Moon, and the
three largest
asteroids, Ceres, Pallas, and Vesta). Given the six orbital
elements at the
epoch, the object's positions at other times are computed by a
numerical
integration, or propagation, of the equations of motion. In
particular, the
object's position is computed at all the observation times, and
given the
position of the Earth and the observatory locations at those
times, the
expected values of the observations themselves are computed
(e.g., the right
ascension and declination positions at the observation time). The
difference
between the computed value for the observation and the value
actually
measured by the observer is called the observation residual. The
orbit for
an object is determined using a process called differential
correction ,
which iteratively adjusts the six orbital elements until the sum
of squares
of all the observations residuals reaches a minimum value. The
final result
of the orbit determination process is called the best-fit or
nominal
solution. Note that the best-fit orbit will not fit all the
observations
perfectly (i.e., the residuals will not all be zero), but it
should fit all
the observations to within their expected accuracies (typically
less than 1
arc-second for optical observations). Also note that when new
observations
of the object become available, a new orbit solution must be
determined in
order to fit the augmented observation set.
It is important to understand that an object's orbit is never
known
perfectly. Although the nominal orbit solution fits the
observations best,
slightly different orbits may still fit the observations to
within their
expected accuracies. There is in fact a whole set orbits around
the nominal
which will fit the observations acceptably well: these all lie
within what
we call the uncertainty region about the nominal orbit. The
'true' orbit is
expected to lie somewhere within this region. As new observations
of the
object are made, the uncertainty region becomes more tightly
constrained and
the range of possible values for the orbital elements narrows. As
a result,
objects which have been observed for decades will have highly
constrained,
well known orbits, while newly discovered objects tracked for
only a few
days or weeks, will have relatively poorly constrained, uncertain
orbits.
Once the nominal orbit and its associated uncertainty region have
been
determined, the object's motion is numerically propagated forward
in time
for up to 100 years in order to determine its close approaches to
the Earth.
These nominal orbit close approach predictions are tabulated in
our Earth
Close Approach Tables along with other uncertainty-related
information such
as the minimum possible close approach distance, and the impact
probability.
The uncertainty-related parameters are computed by projecting the
uncertainty region from the epoch to the respective close
approach times via
so-called linearized techniques. Since these techniques lose
accuracy when
the uncertainties become large, we include only reasonably
certain
predictions in our Close Approach Tables. As a result, close
approaches may
be tabulated decades into the future for objects with well-known
orbits, but
only a few months or years into the future for objects with
poorly known
orbits. On the other hand, Sentry assesses the long-term
possibilities of an
Earth impact for all objects whose orbits can bring them close to
the Earth,
even those with poorly known orbits. To perform this risk
analysis it uses
more sophisticated non-linear methods.
SENTRY IMPACT RISK ANALYSIS
Non-linear analysis is required whenever the uncertainties in a
close
approach prediction are large. The position uncertainty of an
asteroid is
usually relatively small over the time span of the observations,
but it
usually grows, or stretches, as the object's position is
predicted farther
and farther into the future. This uncertainty growth is
especially fast
along the track of the orbit. The evolution of uncertainties can
be
understood using the notion of so-called virtual asteroids (VAs).
Suppose
the uncertainty region around the nominal orbital solution is
filled with a
swarm of thousands or tens of thousands of virtual asteroids,
each having
slightly different orbital elements, but all fitting the
observations
acceptably well. Only one of these virtual asteroids is real, but
we don't
know which one, although the central, nominal orbit is most
likely to be the
real one. The further a VA is from the nominal position within
the swarm,
the less likely it is to represent the real asteroid. If the
three-dimensional positions of the VAs are plotted around the
time of the
observations, the swarm will take the shape of an elongated
ellipsoid.
When the VAs are all numerically integrated forward in time,
their slightly
different positions in space allow each to undergo slightly
different
gravitational nudges (perturbations) from the planets and other
perturbers.
Over time, this swarm of virtual asteroids will spread out along
the orbit
of the nominal orbit, demonstrating how the position uncertainty
ellipsoid
surrounding the asteroid's nominal position evolves into a very
elongated
tube centered on the asteroid's nominal orbit. Long-term orbital
extrapolations can cause the asteroid's position uncertainty tube
to grow to
great lengths, even extending one or more times around the
asteroid's entire
orbit, and close planetary encounters can cause the uncertainty
region to
even double back on itself by folding. This type of numerical
analysis,
whereby many orbits are propagated forward in time to represent a
single
asteroid's position uncertainty region, is the basis of the
non-linear
techniques used by Sentry.
In practice, the non-linear analysis is made computationally more
efficient
if only virtual asteroids along the central axis of the
asteroid's elongated
uncertainty region are integrated forward in time. The assumption
is then
made that virtual asteroids along this "Line of Variations
(LOV)" are
representative of the nearby off-axis portions of the uncertainty
region.
The first step in the risk analysis is to numerically integrate
the VAs on
the LOV forward in time, and detect close approaches to the
Earth. When a
stream of consecutive VAs experience essentially the same close
encounter,
an automatic search is conducted to find the virtual asteroid
that passes
closest to the Earth. The motion of this particular virtual
asteroid and its
own local uncertainty region is then analyzed using linear
techniques to
determine if an impact is possible and, if so, to estimate the
probability
of impact. For pathological cases where an asteroid's uncertainty
region
folds back on itself (due to a previous close planetary
encounter) or where
several complex streams of virtual asteroids are evident, a
second form of
non-linear analysis may be undertaken. This technique, called
Monte Carlo,
samples the complete uncertainty region at epoch, not just the
central axis,
and uses a great many more virtual asteroids. Once again, all the
VAs are
integrated forward to the time of a close Earth approach, and
monitored for
possible impact. If, for example, a total of 100,000 virtual
asteroids were
integrated forward and two of these VAs manage to collide with
the Earth in
the year 2040 then the impact probability for the real asteroid
in 2040
would be approximately 2/100,000, or 1/50,000.
As noted earlier, some of the entries on the individual object
pages are
meant to rapidly communicate and characterize the automatically
generated
results to colleagues for verification and, as such, they are not
necessarily of general interest. Nevertheless, an effort is made
here to
clarify a few of the tabular entries on these pages. The
particular
circumstances of an Earth close approach are studied in the
target plane, a
plane defined as passing through the Earth's center and being
perpendicular
to the incoming velocity vector of the NEA.
see graph at http://neo.jpl.nasa.gov/risk/doc/sentry.html
If we assume a particular asteroid's position uncertainty region
is a long
three-dimensional tube stretched along its orbit, then a
projection onto the
target plane will reduce the uncertainty region to a
two-dimensional strip
centered on the Line of Variations (LOV) and passing a certain
Distance from
the Earth's center. If this Distance is less than 1 Earth radius
then one of
the virtual asteroids is known as a virtual impactor since it can
strike the
Earth. Sigma LOV is a measure of the deviation of the virtual
impactor from
the position of the central, or nominal, virtual asteroid. In
other words,
Sigma LOV is a measure of how well the impacting orbit fits the
available
observations. It is equal to zero for the best-fitting (nominal)
orbit while
orbits with values between -3 and +3 ("3-sigma")
comprise about 99% of the
virtual asteroid swarm. The farther Sigma LOV is from zero, the
less likely
the collision with Earth. Since the intersection of the
uncertainty region
with the impact plane will form a narrow strip on the impact
plane, three
times the Width of this region in Earth radii will include more
than 99% of
the entire localized uncertainty region. Sigma Impact is computed
from
(Distance - R_Earth)/Width and it too is a measure of the impact
likelihood.
It has a value of zero when the LOV intersects the Earth and has
increasing
values as the central axis of the uncertainty region moves away
from the
Earth in the impact plane.
===========
(4) AFTER 9/11: IMPACT RISK UNDERESTIMATED, INSURANCE STUDY WARNS
>From Reiner M. Stoss, Starkenburg Observatory
Hi,
did you notice this article: Versicherungsstudie
"Meteoriten-Risiko wird
unterschaetzt"
http://www.spiegel.de/wirtschaft/0,1518,186881,00.html
Cheers,
Reiner
=============
VERSICHERUNGSSTUDIE: "METEORITEN-RISIKO WIRD
UNTERSCHAETZT"
>From Spiegel Online, 13 March 2002
http://www.spiegel.de/wirtschaft/0,1518,186881,00.html
Seit dem 11. September ängstigt sich die Versicherungsbranche
vor weiteren
unerwarteten Milliarden-Zahlungen. Eine Studie warnt nun vor
einer
unterschätzten Gefahr: vor Meteoriteneinschlägen, die eine
ganze Großstadt
wie Mexiko City zerstören könnten.
München - Nach den Terroranschlägen müsse die Branche lernen,
das Undenkbare
zu denken, fordert die Studie der Münchner Rück. Immerhin hat
der 11.
September auch die Versicherer kalt erwischt.
Milliarden-Zahlungen trugen
dazu bei, dass sich der Jahresgewinn der Allianz halbierte und
bescherten
der Swiss Re den ersten Verlust seit 100 Jahren.
In der Studie Topics haben die Experten aus München die
"Elementarschadensereignisse" wie Stürme und Erbeben
aus dem Jahr 2001
gezählt und ihre Kosten bilanziert. Zugleich versuchten sie zu
ermitteln,
welche anderen Katastrophen die Versicherer in Zahlungsnöte
bringen könnten.
Bombardement aus dem All
Erstmals werde in der Studie das Risiko von
Meteoriteneinschlägen genauer
erfasst, so das Unternehmen. "Die Folgen eines Bombardements
aus dem All"
seien "in stärkerem Maße von der Assekuranz zu tragen, als
dies bisher
angenommen wird". Denn Meteoriteneinschläge würden
Explosionen und Brände
nach sich ziehen, die heute von vielen Verträgen gedeckt seien.
Allein im letzten Jahrhundert seien hundert Meteoriteneinschläge
dokumentiert, heißt es weiter. Eine der bekanntesten
Katastrophen sei der
Absturz eines 50 Meter großen Klumpens aus dem All in Sibirien
im Sommer
1908. Dieses Geschoss explodierte damals einige Kilometer über
der Erde und
erzeugte so eine Druckwelle, die eine Waldfläche von 2200
Quadratkilometer
niederwalzte - das entspricht der Fläche von Mexico City.
In Zukunft mehr Katastrophen - und stärkere
Auch die Risiken und Folgen anderer Naturkatastrophen würden
nicht
angemessen eingeschätzt, betonen die Autoren. Die bisher
teuersten
Naturkatastrophen, der Hurrikan "Andrew" (30 Milliarden
Dollar Schaden) und
das Erdbeben in Northridge, USA (44 Milliarden Dollar Schaden)
hätten noch
weitaus verheerendere Wirkungen haben können, wenn der Sturm nur
eine
geringfügig andere Bahn eingeschlagen oder das Zentrum des
Bebens an ein
einer anderen Stelle gelegen hätte. Selbst eine öffentlich kaum
wahrgenommene Hagelfront könne durch eine Verkettung
ungünstiger Umstände
Milliarden-Schäden anrichten.
Die Folgerungen, die die Rückversicherung aus der Studie ziehen
wird,
scheinen klar: Die Prämien, die Versicherer für das Abwälzen
von Risiken
zahlen müssen, sollten erhöht werden. Dafür führt die
Münchner Rück noch ein
weiteres Argument ins Feld: den Klimawandel. Weil Treibhausgase
die Erde
erwärmten und das Kyoto-Protokoll diesen Trend selbst bei
vollständiger
Umsetzung nicht stoppen werde, seien in Zukunft häufigere und
intensivere
Naturkatastrophen zu befürchten.
Katastrophenkosten 2001 stark gestiegen
Die Kosten, die 2001 durch Naturkatastrophen entstanden, hätten
um 20
Prozent über dem Vorjahresniveau gelegen, bilanziert die Studie.
Insgesamt
beliefen sich die volkswirtschaftlichen Schäden der 700
dokumentierten
Katastrophen auf 36 Milliarden Dollar. Ein einziges zusätzliches
"Größtschadensereignis" hätte gereicht, die Branche
vor eine gravierende
Bewährungsprobe zu stellen.
Als teuerste Naturkatastrophe des Jahres benennt die Studie den
tropischen
Sturm "Allison", der im Juni den Süden der Vereinigten
Staaten überzog und
Schäden von sechs Milliarden Dollar anrichtete. Versichert war
davon
immerhin die Hälfte.
Copyright 2002, Spiegel Online
=============
(5) NATURAL CATASTROPHE BALANCE 2001
Munich Re, 13 March 2002
http://www.munichre.com/index.html
Natural catastrophe balance 2001: No new loss records all told,
but
individual results dramatic, especially an earthquake in India
aber
dramatisch / Again inordinate strain on insurance industry/
Underestimated
loss potentials: first detailed examination of meteorite impact
as an
insurance risk/ Climate change - what are the consequences for
the insurance
industry?
In the latest issue of its study "topics", which has
just been published,
the Munich Reinsurance Company reports, as in the past, on the
natural
catastrophes of the past year. Owing to the fact that risk
managers will
generally have to rethink future loss potentials entirely in the
light of
11th September 2001, this year's publication turns the spotlight
on the
question of hitherto underestimated risks and unidentified loss
potentials
and in this connection analyses the insurance risk emanating
from, etwa
meteorites. Munich Re's experts have also reassessed the effects
of climate
change and have devised more stringent underwriting requirements
as a
result. - As to the statistical section of the study: 2001
emphatically
confirms the long-term trend that insured losses are increasing
much more
sharply than economic losses.
The overall balance in 2001: Insured losses increase sharply
Altogether 700 natural hazard losses were recorded last year. At
around US$
36bn economic losses were about 20% above the previous year's
level (US$
30bn). Insured losses rose to US$ 11.5bn in 2001, thus increasing
by more
than 50% compared with the previous year (US$ 7.5bn). A gigantic
loss event
in the realm of natural catastrophes would have been a severe
test on the
capacity of the global insurance industry in addition to the
burden it has
to cope with from the devastating attack on the World Trade
Center.
More than 25,.000 people were killed in natural catastrophes
during 2001.
This large figure is mainly due to the series of strong
earthquakes at the
beginning of the year. On 13th January an earthquake in El
Salvador, which
had triggered innumerable landslides, claimed the lives of 845
peopleums.
The death toll from the major earthquake in Noch weitaus
dramatischer war
dGujarat in the northwest of India on 26th January was above . Es
14.,000.
Immediately after the quake Munich Re sent its experts into the
disaster
area, where the M 7.7 quake had destroyed tens of thousands of
dwellings as
well as industrial and commercial buildings. The company also sie
organized
an interdisciplinary conference in New Delhi, which took place
around the
anniversary of the quake.. At this conference, future strategies
on risk
management and possible insurance solutions were developed in
collaboration
with Indian authorities and scientists.
Around the globe there were 80 quakes that caused losses in 2001,
producing
economic losses of US$ 9bn and insured losses of about US$ 900m.
As in previous years, insurers' statistics were dominated by
windstorms and
floods. These accounted for more than two-thirds of all events
(480) and no
less than 92% of all insured losses. Tropical Storm Allison,
which hit the
southern part of the United States in June, was the most
expensive natural
catastrophe of the year, triggering an overall loss of US$ 6bn
(more than
half of which was insured). The typhoon season was marked by
numerous strong
storms. Typhoon Nari, which swept over Taiwan in September and
caused major
damage in the capital, Taipei, generated an insured loss of US$
600m.
Meteorites - an underestimated risk?
Risk managers will have to think the unthinkable in the future -
that is
another thing the terrorist attack of 11th September 2001 in the
United
States has shown - and they will have to consider maximum loss
potentials
that are albeit improbable but nevertheless possible. Accordingly
Munich
Re's scientists devote a section in the new study to the first
in-depth
investigation into the risk of meteorite crashes, of which around
100 were
documented last century. These crashes are capable of causing a
wide range
of damaging effects. One of the best known events involved a
meteorite
measuring no more than about 50 metres which came down over
Siberia on 30th
June 1908. The "projectile" exploded at a height of a
few kilometres over
the Tunguska region; the pressure wave flattened about 2,200 km2
of forest
(equal to the area of Mexico City). The study shows that the
effects of a
"bombardment from space" are to be carried by the
insurance industry to a
larger degree than has hitherto been assumed. This is because
meteorite
crashes will probably lead to explosions and numerous fires,
which are
covered in many insurance contracts nowadays.
In connection with the reassessment of risks, the study looks
again at
further loss potentials: The costliest natural catastrophes to
date,
Hurricane Andrew (USA, 1992; economic losses: US$ 30b; insured
losses: US$
17bn) and the Northridge earthquake (USA 1994; economic losses:
US$ 44bn;
insured losses: US$ 15.3bn), could have been three times as
expensive if a
few factors such as the track of the storm or the location of the
hypocentre
had been slightly different. On account of the numerous complex
chains of
cause and effect involved in natural catastrophes surprises and
new loss
records must be reckoned with constantly. A single hailstorm in
Kansas City,
for example, which received hardly any attention even among the
US public,
caused a record loss of around US$ 2bn, of which about 70% was
insured.
In order to minimize the overall risk, above all for insurers
operating on a
worldwide scale, it is necessary to document as fully as possible
the loss
scenarios that have been hitherto underestimated or unidentified.
Climate change as a risk of change
Not only loss events and loss factors but also gradual changes
have been
under constant observation for years. Munich Re's scientists
continue to
assume that climate and environmental changes have an increasing
impact on
the statistics. Dr. Gerhard Berz, head of Munich Re's Geo Risks
Research
Dept.: "Even allowing for a complete implementation of the
Kyoto Protocol,
which will again be the subject of negotiations involving some
170 nations
this year, the emission of greenhouse gases will result in our
having to
contend with the effects of climate change for decades to come,
mainly in
the form of more frequent and more intensive natural
catastrophes."
Dr. Wolf-Otto Bauer, member of the Board of Management of Munich
Re: "The
reinsurers, which bear the lion's share of the losses from
natural
catastrophes, must go on the assumption that the present
underwriting
strategy will no longer be commensurate with the changes."
In view of the
loss trends that can be observed, the conventional practice of
retrospective
underwriting - which involves calculating premiums from the
claims
development of the past - inevitably leads to premium adjustments
lagging
behind and hence to losses increasing. The insurance industry
must think
about how risk-commensurate fluctuation loadings can be
calculated for the
risk of change inherent in climate change. Dr. Bauer: "The
effects of
climate change make adequate prospective underwriting more
essential than
ever."
topics 2001 (PDF format, 1,27 MB)
http://www.munichre.com/pdf/topics_2001_e.pdf
=============
(6) AN ANCIENT ROCK RAIN IDENTIFIED
>From inScight, 12 March 2002
http://www.academicpress.com/inscight/03112002/graphb.htm
After astronauts lugged home piles of moon rocks, planetary
scientists were
surprised to find that the enormous valleys on the moon's surface
are all
nearly the same age. This prompted a controversial theory: that 4
billion
years ago, the adolescent Earth and moon were suddenly pelted by
enormous
space rocks. Now two researchers argue these objects must have
been
asteroids, not comets.
In the 1970s, data from moon rocks revealed that the moon's
largest valleys,
or "basins," were formed between 3.88 billion and 4.05
billion years ago.
That implied that the moon and nearby Earth had suffered a
torrential
bombardment of massive rocks. (Evidence of this on Earth has been
obliterated by the planet's geologic activity, which continually
renews its
surface.) For decades, scientists have wondered how the other
young planets
conspired to throw things at the Earth and moon. Some speculated
that as the
outer planets formed or shifted orbits, they deflected a burst of
both
comets and asteroids into the inner solar system.
But David Kring of the University of Arizona in Tucson and
Barbara Cohen of
the University of Hawaii, Manoa, argue that the objects were
asteroids
alone. They first compared moon rocks and bits of asteroids, and
they found
that they contain similar concentrations of certain trace
elements. Then
they tested whether the asteroid belt between Mars and Jupiter,
the likely
culprit in an asteroid bombardment, was disrupted at the time.
The pair
compared levels of key isotopes in asteroids that had fallen from
the belt
and found that they were colliding about 4 billion years ago,
suggesting
that some flew out of the belt then. Finally, they point out that
a
meteorite found in Antarctica and originally blasted off the face
of Mars
appears to have been partially melted by an impact at about the
time Earth
and the moon were pelted. This bolsters the theory that the
entire inner
solar system was blasted with asteroids when the moon's basins
formed, the
researchers report in the February issue of Journal of
Geophysical
Research--Planets.
But the asteroids-only interpretation isn't a sure thing, says
Clark Chapman
of the Southwest Research Institute in Boulder, Colorado. The
trace elements
in the moon rocks may have been deposited in smaller asteroid
impacts after
comets formed the basins, he says. Meanwhile, William Hartmann of
the
Planetary Science Institute in Tucson questions whether a
bombardment--from
either comets or asteroids--happened at all. The moon's basins,
he argues,
might all have the same age simply because before 4 billion years
ago, the
still-forming moon suffered so many blows that the surface
couldn't settle.
--ADRIAN CHO
© 2001 The American Association for the Advancement of Science
==============
(7) DEADLINE APPROACHES FOR NEXT ROUND OF SHOEMAKER NEO GRANTS
>From Ron Baalke < baalke@jpl.nasa.gov
>
http://www.planetary.org/html/news/articlearchive/headlines/2001/neograntann.html
Deadline Approaches for Next Round of Shoemaker NEO Grants
by Melanie Melton
Planetary Society
March 12, 2002
Those interested in applying for the The Planetary Society's next
round of
Shoemaker Near Earth Object (NEO) grants have only three more
weeks to do
so.
Those amateur or professional astronomers interested in studying
Near Earth
Objects can apply for the grant by filling out an application
form and
sending it to The Planetary Society by March 31, 2002.
The application form can by found here:
http://www.planetary.org/html/neo/SocietyProjects/ShoemakerGrant/NEOGrantForm.html
The Shoemaker NEO grant program was established by the Society in
1997, in
an effort to advance the study of Near Earth Objects. Grant
recipients in
the past have been both individuals and groups, amateur and
professional
astronomers, all interested in studying asteroids and comets in
Earth's
vicinity.
For this round of grants, the Society's international advisory
group
reviewing the proposals will be considering three different
categories:
Observation Programs, NEO Research Programs, and International
Collaboration
in NEO Observations.
With several asteroid detection programs in place at major
observatories
around the country, there has been a dramatic increase in
asteroid detection
within the last year, creating a long list of objects in need of
follow-up
observations. As a result, special consideration will be given to
observers
interested in conducting follow-up NEO observations, especially
those
capable of detecting objects fainter than magnitude V= 19.5 or
so.
* For more information about the Shoemaker NEO Grant Program
http://www.planetary.org/html/neo/SocietyProjects/ShoemakerGrant/NEOGrantindex.html
* For NEO Grant Guidelines
http://www.planetary.org/html/neo/SocietyProjects/ShoemakerGrant/NEOGrantGuidelines.html
* For the application form
http://www.planetary.org/html/neo/SocietyProjects/ShoemakerGrant/NEOGrantForm.html
============
===============
(8) "MARS EROSION FEATURES CARVED BY LIQUID CO2, NOT RUNNING
WATER"
>From Harvey Leifert < hleifert@agu.org
>
American Geophysical Union
12 March 2002
AGU Release No. 02-09
For Immediate Release
Contact: Harvey Leifert
(202) 777-7507
hleifert@agu.org
Martian Surface Features Were Eroded by Liquid Carbon
Dioxide, not Running Water, Researchers Say
WASHINGTON - Scientists have provided new evidence that liquid
carbon
dioxide, not running water, may have been the primary cause of
erosional
features such as gullies, valley networks, and channels that
cover the
surface of Mars. Research suggesting that condensed carbon
dioxide found in
Martian crust carved these features is reported by Kenneth L.
Tanaka and
colleagues at the U.S. Geological Survey in Flagstaff, Arizona,
and the
University of Melbourne, Australia, will appear this month in
Geophysical
Research Letters, published by the American Geophysical Union.
Using Mars Orbiter Laser Altimeter (MOLA) data, Tanaka and his
colleagues
constructed elevation profiles of the Hellas basin, which, at
2000
kilometers [1,240 miles] wide and nine kilometers
[six miles] deep, is the largest well-preserved impact basin on
Mars. By
examination of digitally created elevation profiles with
500-meter [2,000
foot] resolution, they found that the volcanic
regions of Malea and Hesperia Plana, along the rim of the Hellas
basin, are
several hundred meters [yards] lower than adjacent rim sectors.
Additionally, these areas lack the prominent triangular peaks,
called
massifs, that are common in nearby areas.
Along the inner slopes of these regions, the researchers found,
however,
evidence of old massifs covered by volcanic rocks. They are too
low to be
covered, if there were volcanic activity today. The researchers
suggest as
an explanation that prior to volcanic activity, these regions
along the rim
of the basin resembled nearby areas, but were eroded to their
present-day
elevations following the emplacement of the volcanic rocks.
Tanaka and his colleagues propose a "magmatic erosion
model" to explain the
features of the volcanic areas of Malea and Hesperia Plana,
suggesting that
they underwent catastrophic erosion
associated with explosive eruptions of molten rock. They suggest
that liquid
in the Martian crust was heated when molten rock, or magma, rose
to the
surface. As the liquid was heated, it expanded, until the
pressure of
overlying material was too great, and an explosive eruption
occurred,
shattering overlying rock, and causing it to move with the magma
in an
erosive debris flow.
The authors believe that the fluid in the crust along this area
of the rim
of the Hellas basin was mainly liquid carbon dioxide. A debris
flow
dominated by carbon dioxide would flow faster and farther than a
water-based
flow, they say. Also, carbon dioxide is more volatile than water
at lower
temperatures, and the cold temperatures found on Mars would mean
that less
carbon dioxide-based magma would be required to produce the
observed erosion than magma
containing mainly water.
The researchers suggest that this mechanism of erosion can also
explain
collapse features and channels elsewhere on Mars. They also note,
however,
that their model is based on a variety of assumptions that must
be further tested.
**********
Notes for journalists:
The paper by Kenneth L. Tanaka, Jeffrey S. Kargel, David J.
MacKinnon, Trent M. Hare [Astrogeology Team, U.S. Geological
Survey], and Nick Hoffman [University of Melbourne],
"Catastrophic Erosion of Hellas Basin Rim on Mars Induced by
Magmatic Instrusion in Volatile-Rich Rocks," will be
published
online within the next two weeks and later in the print edition
of
Geophysical Research Letters. Its citation, which is to the
online
version, is 10.1029/2001GL13885, 2002.
Journalists (only) may obtain a copy of the paper (11 pages) by
pdf file or
by fax on request to Emily Crum at ecrum@agu.org
. Please indicate the format
desired and include your full name, name of publication, and your
email
address or fax number. The paper and this press release are not
embargoed.
The authors may be contacted as follows:
Kenneth L. Tanaka: +1 (928) 556-7208 or ktanaka@usgs.gov
Jeffrey S. Kargel: +1 (928) 556-7034 or jkarge@usgs.gov
David. J. MacKinnon: +1 (928) 556-7162 or
dmackinnon@usgs.gov
Trent M. Hare: +1 (928) 556-7126 or thare@usgs.gov
Nick Hoffman: +61 3 9479 1516 or Nick@3D-geo.com
###
============================
* LETTERS TO THE MODERATOR *
============================
(9) SPACE WEAPONS, EARTH WARS: NATURAL METEOROIDES AS WEAPONS
>From James Perry < AJDPerry@aol.com
>
Benny,
There is a new RAND study entitled "Space Weapons Earth
Wars" -- I think
CCNet readers will be interested in Appendix C ("Natural
Meteoroids as
Weapons"):
http://www.rand.org/publications/MR/MR1209/MR1209.appc.pdf
James Perry
==============
(10) C/2002 C1 (IKEYA-ZHANG)
>From Mark Kidger < mrk@ll.iac.es
>
Benny:
With more data available now and a better time base I have been
looking more
closely at the light curve of Comet Ikeya-Zhang. According to the
data that
I have at hand, the comet has been brightening rapidly since
discovery,
although not as fast as has been suggested. Seichii Yoshida had
found a
light curve solution of
m1 = 6.8 + 5 log Delta + 10 log r
which I used as my starting point. It gives a quite good fit to
the data,
although it would make the comet a little too bright in early
February. The
best fit that I obtain is
m1 = 7.2 + 5 log Delta + 11(+/-0.5) log r
This would give a peak of around magnitude 3.5 in the next few
days,
consistent with the fact that the data that I am receiving from
fairly
experienced observers still has the comet around magnitude 4.
The comet is brightening quite fast, but not as fast as has been
suggested.
Certainly though, the light curve is typical of a rather gassy
object. What
is interesting is that these rarely brighten fast close to the
Sun. Images
show a tremendous amount of activity in the tail. This is a very
spectacular
object in photographs and CCD images, even though visually the
low altitude
and twilight robs it of part of its spectacle.
Readers can see the fit to the light curve and an extrapolation
for the
future in:
http://www.iac.es/galeria/mrk/Light_2002c1.gif
I would expect the comet to fade faster after perihelion than it
has
brightened, to the extrapolation may be slightly optimistic.
Visibility
should still be reasonable into April, although this is never
going to be a
very easy naked-eye object.
Mark
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