Randall Carlson's Work: Striking similarities (Comets, Geology, Catastrophism etc.) through Decades of meticulous research?!

[Cosmos]

[...]In the next post I'll post a link to the article Randall is quoting. Again, this article was hard to find on the Internet and seems to be incomplete. In fact I could find only one place on the net that has republished it, and probably not all of it.

Found it on two places now, one here and on here. It appears this original is from the year 2000.

I'll reprint the text below, in case it goes missing on the internet. Notice that in the second link above, another text is mentioned at the beginning, where Dr Benny Peiser is quoted. That text is linked back to the original article from "discovery.com", that seems to have been deleted since... You will find that one also reprinted in the second quote below.

Impact Events Shaped Rise Of Civilization

Liverpool - March 7, 2000 -

In a presentation to the Annual Meeting of the American Association for the Advancement of Science (AAAS), Dr Benny Peiser of Liverpool John Moores University, presented new evidence suggesting that more than 500 impact events of extraterrestrial orgin have punctuated Earth during the last 10,000 years.
The great majority (70%) of these events have been of the Tunguska-type class of atmospheric impacts with an average energy yield of between 20 and 100 Mt TNT. However, more than 100 surface impacts, including more than a dozen oceanic impacts, are believed to have repeatedly devasted whole regions, small countries and early civilisations around the globe.

In a worst case estimate, Dr Peiser said that up to eight climatic downturns detectable in the geological and climatological records of the Holocene may be directly associated with multiple impact events.

"Episodes of increased cometary or meteoric activity punctuating societal evolution should be looked upon as potential agencies determining the rise and fall of ancient civilisations.

Both the emergence and the collapse of human cultures, the Pleistocene-Holocene transition and the Neolithic Revolution, the onset and collapse of the Bronze Age civilisations, and even the collapse of the Roman Empire may be associated with episodes of increased cosmic activity and multiple impacts that may well have included incidents of cosmic dust loading."

While most of these impacts occurred over unpopulated areas of the globe, there are historical accounts about devastating cosmic catastrophes. According to a number of Chinese records, about 10,000 people were killed in the city of Chi'ing-yang in 1490 AD due to the break-up of a small asteroid.

About a dozen hypervelocity impact craters that date from the Holocene period (i.e. since the end of the ice age) have been discovered to date. The majority of impacts, however, that occurred during this crucial period of societal evolution have not been detected yet.

According to Dr Peiser, "the 14 known Holocene impact craters most certainly paint a rather deceptive picture of our past. The fact that no massive impact crater dating to the Holocene has been detected, has led to the belief that no hemispheric or global impact disaster can possibly have happened. However, this is a widespread delusion."

Yet there still is a regretable lack of interest by the scientific community to scrutinise the Holocene for major impact events.

"The widespread ignorance of such cosmic disasters in historical time is due to the limited research focus on crater producing events. Yet only 3% of fatal impacts produce a hypervelocity surface crater on land", Dr Peiser points out.

Tunguska-like impacts or "Super-Tunguskas" are thus taken out of the equation. Due to their catastrophic detonation above ground (or in the oceans), they often leave no obvious fingerprints behind.

Dr Peiser also presented new impact simulations that estimate expected fatalities of cosmic impacts for the next 10,000 years. Without the establishment of effective strategies of planetary defense in the future, more than 13 million people are expected to die as a direct result of impact catastrophes in the next ten millennia.

"We can, and indeed have to live with smaller, Tunguska-type impacts. There is little we can do about them. But we need to prevent the impact of larger objects which threaten the stability of our civilisation.

"Unless we start planning ahead and develop the technology for the deflection of this threat, cosmic impacts will inevitably lead to major disasters in the future", Dr Peiser stressed.

Based on computer simulations that take into account the current flux of near-Earth objects, a typical 10,000 years period with a constant human population of 5 billion can expect to experience: *110 fatal impacts resulting in a total of 13 million fatalities (an average of 120,000 fatalities per event).

• 300 "Tunguska" style airbursts over land, with 80 of these producing fatalities (roughly 1 fatal event per century).
• 12 ocean impacts that produce tsunami, with an average of 500,000 fatalities per event.
• 4 land impacts, with an average of 500,000 fatalities per event.

"These estimates are based on the assumption that the current asteroidal and cometary flux will be constant in time and quantity over the next 10,000 years. However, there is growing evidence to suggest that there have been peak levels of meteoritic activity in the past that differed significantly from the cosmic calm of the last 300 years", Dr. Peiser pointed out.
In January, a UK Task Force was set up by Lord Sainsbury, the Science Minister, to look into the way in which Britain should respond to the impact hazard and how it can contribute to the international efforts prevent major impacts from happening in the future.

ASTEROID IMPACTS SHAPED HISTORY?

From DISCOVERY.COM, 23 February 2000
http://www.discovery.com/news/briefs/20000223/space_impacts.html

The role of the multi-megaton impacts of comets and asteroids could be
very significant, says Benny Peiser, a social scientist from Liverpool
John Moores University in England.

"The focus over the years has been the big events," Peiser says,
referring to the alleged global catastrophe that followed the impact of
an asteroid with the Earth 65 million years ago -- wiping out the
dinosaurs.

But smaller events similar in size to the 1908 Tunguska blast that is
believed to have leveled 2000 square miles of forest could play a big
role in history, Peiser explained to scientists on Saturday at the
meeting of American Association for the Advancement of Science in
Washington, D.C.

The Tunguska event left no crater because the lightweight comet or
asteroid exploded in the atmosphere before reaching the ground,
scientists believe.

Similar extraterrestrial blasts in history might have triggered the
demise of Bronze Age civilizations in the Mediterranean, account for the
mysterious disappearance of certain cultures in the Americas, and
explain the rise of apocalyptic religions and biblical references to
localized disasters, says Peiser.

It also would mean that we are more vulnerable to such disasters than
currently thought.

"We haven't got any indication of when another asteroid might come
close," says Peiser.

Astronomers, however, are skeptical of Peiser's danger assessment.

"I can't say it's never happened," says asteroid impact specialist
Richard Binzel of the Massachusetts Institute of Technology, regarding
the possibility of a Tunguska-sized event hitting a populated area. "But
on the entire surface of the Earth the area of destruction is very
small."

In other words, the chances are tiny, and were downright miniscule when
there were fewer people and fewer cities.

As for the odds of another global catastrophe like the one that
supposedly killed the dinosaurs, says Binzel, there's a one in 10,000
chance of it happening in any given century.

"We're just more conservative" in danger estimates, Binzel says.

Copyright 2000, Discovery.com

 

[Cosmos]

[...] Pay a special attention to the many details Randall throws in there every now and than in passing. Like the Burckle crater event (that we will see in much greater detail in other videos soon. Very interesting!)

What follows is a short 10 minute section about the Burckle crater event approximately 5000 years ago, which was very likely global and cataclysmic in extent and involved at least 600 foot tall Tsunami waves (probably several hundred feet higher in actuality, when it hit land). An object hit the middle of the Indian ocean and created a 18 mile (30 Kilometers) wide crater under 12,500 feet (3800 Meters) of water!

In a number of other videos, Randall also talks about this event in more detail. Notice also that the Holocene Working Group suggests that possibly 80% of the world’s population was wiped out during this event. Also notice the satellite images Randall pulls up from the 600 foot high Chevrons (sediment deposits from this Tsunami) on Madagascar and other coastlines and how he explains what you can see there in terms of geology and water behavior and shows it from the down to earth perspective as well. HUGE!

The description of the video says:

Burckle Crater Impact and Mega-tsunami -Cosmography101 class 18.2 excerpt w/ Randall Carlson 2008

Class 18 part 2 excerpt: The Burckle Crater - Was there a global disaster 5200 years ago? Cosmography101 with Randall Carlson Overview/topics Include: Burckle Crater; tsunami effects / Chevrons – 600’ high sediment deposits on Madagascar Deep sea microfossils fused with extra-terrestrial metals “Splooge” on the western coast of Australia Possible areas to study along coasts of Sri Lanka and South African coasts Site of the crater in the Indian Ocean Holocene Working Group suggests possibly 80% of world’s population wiped out

Here is the video:

 

[mrtn]

I wonder about these canyon-like structures shown in the video, also visible here:

Scientists Debate Evidence of Ancient Megatsunami

Giant tsunamis may have helped to shape the world around us today.

news.nationalgeographic.com

I can't find anything like that on google maps:

Fenambosy Chevron · Madagaskar

★★★☆☆ · Berggipfel

www.google.com

I also wonder what features one would expect on Reunion and Mauritius which are much closer to the Burckle Crater:

30°51'54.0"S 61°21'54.0"E · -30.865000, 61.365000

www.google.com

Either they were washed over completely (see eroded mountains/volcanos on Reunion, but thats 3000m high!), or in the case of Reunion the coast is just to steep to be much affected by a tsumani.

 

[Cosmos]

I wonder about these canyon-like structures shown in the video, also visible here:

Scientists Debate Evidence of Ancient Megatsunami

Giant tsunamis may have helped to shape the world around us today.

news.nationalgeographic.com

I can't find anything like that on google maps:

Fenambosy Chevron · Madagaskar

★★★☆☆ · Berggipfel

www.google.com

Actually, you find exactly what Randall ist talking about in the google maps link above. See what Randall says about it again; the v shapes you can see on google maps, the tips of those structures are the chevrons you see from the ground as you can see in the first picture. You need to develop a bigger eye, or view of things, to be better able to recognice those structures. It is also useful to know and be able to imagine how big structures look up close from the ground when you can‘t directly see the bigger picture as from a plane or a satellite.

The eye for that needs to be developed, the same way you need to develop an eye for technical drawings or building plans for example and the demensions involved. The problem here is that many of those structures are so huge that without a sattelite view it is very hard to understand from the ground.

 

[Voyageur]

What follows is a short 10 minute section about the Burckle crater event approximately 5000 years ago...

Very interesting these chevrons. It looks (estimation from the scales) that the Tsunami went at least, if not more, then 14 km inland and on the Austrailain coast it was at least up to 3 miles.

 

[Voyageur]

You need to develop a bigger eye, or view of things, to be better able to regocnice those structures and also how big structures look up close from the ground when you can‘t directly see the bigger picture as from a plane or a satellite.

Yes, and once seeing that way it would be hard not to recognize them wherever they can be found. The height of the chevrons is impressive, too.

 

[mrtn]

But when I zoom in there and use the 3D mode and cntrl/mouse to look around I can't find anything as steep as in the image, and the edges of these deposits are rather bulgy and have a shape opposite to that canyon-like edges that look more like eroded rock than deposited sediments. Also in the Image the hill is darker / has vegetation and the lower ground is lighter / emtpy sediments (or farmland). But in the chevron that's other way round (sand on top). Sorry, I just can't make the connection. Maybe the image is from somewhere up the Linta river bed.

 

[Cosmos]

Maybe the image is from somewhere up the Linta river bed.

Possibly yes. Notice that there are many, many of those v shaped chevrons scattered all over the land if you zoom out, all in a consistent direction which can precisely be used for calculating where the water was coming from and how it behaved. Also notice, as Randall explains in a number of lectures, the behavior of water is a scalable phenomenon, similarly to plasma phenomena for example. He talks about the phenomena which is called „scale invariance“ in that context too, which is also something you can see in Mandelbrot phenomena discussed in mathematics. So the effects you can see on a small scale that water is creating on where it flows and how it behaves, can be scaled up and the overall pattern remains the same.

By the way, as far as I know, the scientists who discovered Burckle crater and the associated chevrons, where able to find the crater in the first place by exactly calculating where the different chevrons on the different coastal planes on the islands and continents were pointing at, that are located all around the Indian ocean.

It all pointed to one specific region in the Indian ocean where they then found the crater exactly at the point expected from those calculations.

Edit: Spelling

 

[Cosmos]

But when I zoom in there and use the 3D mode and cntrl/mouse to look around I can't find anything as steep as in the image, and the edges of these deposits are rather bulgy and have a shape opposite to that canyon-like edges that look more like eroded rock than deposited sediments. Also in the Image the hill is darker / has vegetation and the lower ground is lighter / emtpy sediments (or farmland). But in the chevron that's other way round (sand on top).

First, we don’t know which exact Chevron of the many that exist in that and other areas is depicted in that picture.

Second, the 3D function on google maps is very unfriendly to get a real sense of what you would be looking at from the ground level, height wise. All on google maps in the 3D option looks pretty flat even though it isn‘t. You can check that out very easily for yourself. If you have something high, like a mountain or hill near to your place (that you know how high it looks like in real life from a ground perspective) take a look how it looks like on google maps 3D; almost totally flat... Even higher mountains look completely flat on google maps 3D.

Take for example Mount Kilimanjaro, which towers a staggering 4900 Meters above the surrounding plains and still looks basically flat on google maps 3D.

Mostly the issue here is that you can‘t really convert a three-dimensional image into a two-dimensional screen picture. That is why ground perspective pictures of those tsunami features are coming much closer to how it really looks in 3D on the ground level.

Edit: Spelling

 

[Voyageur]

Had a watch of this class (18) and follow ups to class 18.3. This one starts with Velikovsky and he challenges some of his hypothesis, and rightly so, while also acknowledging his other works.

Carlson lays out some interesting examples (that may aid in the discussion on the Ice Age thread dealing with the buried planes and core samples) and use the zodiac wheel of ages to chart changes in time while documenting events.

 

[Cosmos]

Very interesting these chevrons. It looks (estimation from the scales) that the Tsunami went at least, if not more, then 14 km inland and on the Austrailain coast it was at least up to 3 miles.

Also notice, as Randall explains es well, what you are looking at is only the remains of the flood (chevrons for example) which means that the water that created it was at least that high, possibly though several 100 feet higher than that, which means the devastation of the water probably reached even farther inland.

But just you wait, even those monstrous tsunami waves about 5,000 years ago are very likely pretty small ones compared to those that Randall has documented that have devastated huge amounts of landmass, not only in America, at the end of the last ice age. There too he makes a pretty solid and I would say very hard to deny case for this humongous floods and associated impacts on the ice sheets and possibly the oceans.

Not to mention the over 500,000 Carolina Bays that are dated to the same time and which he discusses in great detail in a series of lectures too.

Edit: Spelling

 

[Voyageur]

But just you wait, even those monstrous tsunami waves about 5000 years ago are very likely pretty small ones compared to those that Randall has documented that have devestated huge amounts of landmass, not only in America at the end of the last ice age. There too he makes a pretty solid and I would say very hard to deny case for this humongous floods and associated impacts on the ice sheets and possibly the oceans.

Oh yes, going inland a dozen or so kilometers is nothing compared to what has happened with hundreds of miles; often cited by even Velikovsky himself. Which segways into what Randall said of him. Yes, agreed about the Jupiter problem of the Venus birth rather than as a interloper, s it is not that both Venus and Mars were not big factors in time - possibly even in the transferance of water to earth. The other thing is that V was originally working off biblical accounts and cross referencing to geological and myth accounts (without the knowledge we have today) and he makes some interesting cases, as does Randall. He also was refining his ideas along the way and did not have the whole banana, yet he did have some of the cosmic electrical aspects down, and think he had even refined his ideas about plate crust slippage as opposed to complete pole reversal; not sure if or in which book he says this.

Around here, the inland oceans of Alberta left over from this stage 100 million years ago (if accurate):

let loose south along with the Columbia gorges water transfer and the events in Klamith falls and the Missoula floods:

to name a few, speak to what you are saying of the ice sheets melt - and it was fast and deeply penetrating. Right across the ice sheets it was the same to the lands of the south (sometimes drainging north also).

Aside from the ice sheets (interconnected too), they way it looks to me is that with oceans being 70+% of this planet while being struck by a large comet is not the simplistic model (gotta love models) that this states it is - If an Asteroid Hits the Ocean, Does It Make a Tsunami? (Probably Not) and it is probably more like this animation. Anyway, it seems akin to rocking a bathtub, and the splash can be big - walls of water and a long way inland big.

 

[flashgordonv]

I must say I am finding it quite ironic that we are expecting the (imminent?) arrival of comets and/or a mini ice age to effectively finish off our world and at the same time the climate alarmists are convinced that AGW and extreme heat is going to finish off our world. There are now large numbers of people posting on FB and Twitter about how it is too late, abrupt global warming has begun and we are all going to die soon.

Almost as if they are picking up on "as above, so below"

 

[Voyageur]

It is easy to get carried away by something that societies in modern times have not experience - comet induced tsunami, so a person can carry forward what they understand. The science (some of it), though (and the physicist would need to weigh in), has some different hypothesis as explained by this link above that I was dismissive of. The evidence of the Burckle crater event with coastal chevron evidence inland seems to say something quite different (more aligned with what one might think). Good opportunity to look for more of these chevron's as Randall suggests.

The argument against large tsunami propagation from a comet ocean impact was looked at a bit more after posting, and it still seems somewhat contentious, although it leans towards the minimal - here it is below for a comparative look:

But when I zoom in there and use the 3D mode and cntrl/mouse to look around I can't find anything as steep as in the image, and the edges of these deposits are rather bulgy and have a shape opposite to that canyon-like edges that look more like eroded rock than deposited sediments. Also in the Image the hill is darker / has vegetation and the lower ground is lighter / emtpy sediments (or farmland). But in the chevron that's other way round (sand on top). Sorry, I just can't make the connection. Maybe the image is from somewhere up the Linta river bed.

Hear what you are saying, and my 2 cents compares it to looking at alluvial fans downstream from satellite or areal images; you can well see the fan yet it is hard to get orientation around the height details unless standing there. If you had stereoscopic glasses and two good aerial photographs you could get a sense of height like these - and even measure it.

EDIT: forgot to add something which might be even better, is to look for Lidar maps of what is being sought.

• Tsunami generated by impacts

  Although, for a given location on the Earth's surface, the risk of a "direct" hit from an asteroid is slight, researchers realized that an ocean impact had the potential to be much more destructive due to the effects of tsunami. An airburst explosion is a three dimensional event and energy decreases according to the square of the distance but a radiating ocean wave is a two-dimensional phenomenon and, in theory, energy decreases in proportion to distance. Since the early 1990s some advanced computer simulations have been conducted to estimate the effects of asteroid impacts above deep oceans.
  The dramatic picture by Don Davis is a little misleading. When an asteroid hits the ocean at 70 000km/h there is a gigantic explosion. The asteroid and water vaporize and leave a huge crater - typically 20 times the diameter of the asteroid (that is, a 100m asteroid will create a 2 kilometre diameter crater). The water rushes back in, overshoots to create a mountain of water at the middle and this spreads out as a massive wave - a tsunami. The centre of the "crater" oscillates up and down several times and a series of waves radiate out. An idea of the mechanism can be obtained by bursting a balloon in a bathtub.
  

  ​

  
  At this stage there are considerable differences in asteroid/tsunami predictions between the researchers. For a review of the methods see Ward & Asphaug (1999). After presenting their predictions of risk to coastal areas these authors note that "Being about ten times less than Hills et al. (1994) and perhaps ten times greater than Crawford and Mader (1998), our predictions split the field".
  
  The main items of contention appears to be:
  
  

  • the initial size of the wave - based on analysis of the size and shape of the "crater" and the manner in which it collapses, and
  • the rate at which a tsunami from an asteroid impact dissipates as it travel. {{my note here would be what are the coast lines telling us as Randall explains}}

  [*][*]
  

  500m diameter asteroid impacting 5km deep ocean.​

  
  

  From Crawford & Mader 1998.​

  
  

  

  Crawford & Mader (1998) explain that, for an impact to produce a coherently propagating wave (one that does not dissipate substantial energy when it travels over great distances) the "cavity" must be 3 to 5 times broader than the depth of the ocean. Using a rule-of-thumb (derived from simulations) that the cavity diameter is 20 times the asteroid diameter then, for a typical ocean depth of 4km, the impactor must be at least 1 km in diameter to produce a coherent wave. On this basis, for asteroids smaller than about 1km, the wave will dissipate considerably as it travels over thousands of kilometres of ocean. Table 2 - Estimated deepwater wave height (above sea level) at a point 1,000km from an asteroid impact (selected research results)

• 
  
  

  Stony Asteroid Diameter	Hills & Goda (1998) (their Figure 1)	Ward & Asphaug (1999) (their Figure 6)	Crawford & Mader (1998) (their Table 1)​
  200m​	1m (5m from equation)​	5m​	negligible​
  500m​	11m​	15m​	<2m​
  1 km​	35m​	50m​	6m​

  How can we resolve these differences in order to carry out a risk assessment? There have been no detected asteroid impacts into an ocean on Earth so it is difficult to verify the models. However, the CTH computer code used by Crawford and Mader successfully predicted the consequences of the impact of Comet Shoemaker-Levy 9 with Jupiter. In the (fortunate) absence of experimental evidence on the Earth, the conservative results produced by Crawford & Mader have been used in the following analysis. In other words, it is assumed that asteroid impacts will generally produce non-coherent waves which dissipate quickly.There may be cases where an asteroid impact produces coherent waves but this would be due to a combination of unusual conditions, such as shallow water, rather than the norm.
  In the case of asteroids 200m and larger there is likely to be an impact into the ocean. For objects under this diameter there is a reduction in the size of the deepwater wave due to energy dissipation in the atmosphere. Speed, trajectory, density and strength of the object can affect the nature of the explosion. There does not appear to be an empirical formula available to deal with these smaller objects and it is possible that the smaller asteroids produce no appreciable waves. On the other hand, in the case of serious tsunami generated by earthquakes the energy involved is estimated to be equivalent to about 2 Megatons of TNT (Yabushita 1998). The impact by a 100m asteroid typically involves kinetic energy of about 75Mt so it would only involve the conversion of about 3% of this energy to wave energy in order to produce a serious tsunami - albeit, the tsunami could quickly dissipate, compared with an earthquake generated tsunami.
  
  On balance the following conservative values have been used for risk assessment. These are based on extrapolation of Crawford and Mader data. Note that compared with Table 2, the range has been reduced to 100km to obtain reasonable values for the smaller asteroids.
  
  Table 3. Estimated deepwater wave height (above sea level)
  at a point 100km from asteroid impact (based on extrapolation of Crawford & Mader)
  
  

  Asteroid Diameter (m)	Deepwater Wave Height (m)
  50​	0.12​
  100​	0.7​
  200​	3​
  500​	22​
  1 km​	70​
  2 km​	230​

  
  
  Estimated risk to coastal locations
  Taking the New Guinea experience as a reference level, it is assumed that a tsunami with a 10m run-up will be of concern to low-lying coastal areas. This risk is estimated in the following steps:
  
  
  
  
  
  
  • a) Determine the run-up factor W for the location in question.
    b) Determine the critical deepwater wave height that will produce a tsunami with a run-up height of 10m (H = 10 / W).
    c) For each size of asteroid, determine the distance over which a deepwater wave will need to travel before it has reduced in size to the critical height determined in step (b). This will be the "danger radius" for this combination of run-up factor and asteroid size.
    d) Determine the area of a semi-circular area of ocean with a radius equal to the distance derived in step (c).
    e) Calculate the probability of an impact within the area derived in step (d).
    Using a log-log plot of the Crawford and Mader data (see Appendix), the following estimates of danger radius have been derived by (gross) extrapolation.
• Using a log-log plot of the Crawford and Mader data, the following estimates of critical radius have been derived by (gross) extrapolation. Table 4
  "Danger radius": Estimated radius from impact
  for a tsunami 10m or higher at the shore
  
  

  Stony Asteroid	Tsunami Run-up Factor
  Diameter	5	10	20	40
  (m)	Distance from impact (km)
  50​	10​	20​	40​	60​
  100​	40​	70​	130​	230​
  200​	140​	250​	460​	820​
  500​	800​	1400​	2500​	4400​
  1000​	2800​	5000​	9000​	16 000​

  It is noted that, irrespective of run-up factor, the radius derived for a 50m asteroid is about the same as the radius of direct devastation for the Tunguska event.
  Impacts by asteroids 2km and larger exceed the global catastrophe threshold and are disregarded for the purpose of analysing tsunami effects.
  
  For most coastal locations the surface area of ocean which poses a tsunami threat is a semi-circle with a radius R equivalent to the distances derived in the above table. This radius is, however, limited by the size of the ocean. An area corresponding to 30% of the surface area of the Earth has been used for this limit (the approximate size of the Pacific Ocean). Applying equation (1) to the resulting semi-circular areas provides the following estimates of average intervals between events:
  Table 5 - Estimated interval between major tsunami events
  (tsunami height 10m or more)
  
  

  Stony Asteroid	Tsunami Run-up Factor
  Diameter	5	10	20	40
  (m)	Average interval between tsunami events (years) for a single location ("city") on the shore of a deep ocean.
  50​	-​	81 million​	20 million​	9 million​
  100​	-​	66 million​	19 million​	6 million​
  200​	83 million​	26 million​	8 million​	2 million​
  500​	20 million​	7 million​	2 million​	670 000​
  1,000​	4 million​	1.3 million​	400 000​	330 000​
  All*​	3 million​	1 million​	300 000​	190 000​

  *All = 1/ ( 1/T50+ 1/T100 + 1/T200 + 1/T500 + 1/T1000)
  In all cases it appears that risk of serious tsunami from asteroids 200m diameter and smaller is much less than for larger objects.
  
  For a given coastal location the predicted average interval between 10m tsunami events (bottom row from Table 5) can be compared with the average interval between "direct" impacts (Table 1) to derive the relative risk for that location compared with an inland location (that is, a location which is not vulnerable to a 10m tsunami). Note that this is independent of the actual rate of impacts.
  
  Table 6 - Relative risk of coastal location compared to inland location
  
  
  

  Tsunami Run-up factor	Relative risk due to all types of impact​
  0 (inland)​	1​
  5​	4​
  10​	14​
  20​	46​
  40​	74​

  
  
  
  This tentative analysis suggests that the risk to a low-lying coastal area from tsunami generated by asteroids is significantly greater than the risk from a "direct" impact by such objects. The average interval between such tsunami events is estimated to range from about 190,000 years for a location with a run-up factor of 40 to about 3 million years for a location with a run-up factor of 5. These compare with an average interval of 14 million years for a "direct hit".
  
  Discussion
  Comparison with the risk analysis by others
  In a paper titled "Asteroid impact hazard: a probabilistic hazard assessment" to be published in Icarus (and findings presented at the Tsunami Symposium in May 1999), Ward and Asphaug (1999) set out a comprehensive method of determining the impact tsunami risk. This analysis is based on methods they have developed for assessing earthquake risk. Probabilities are derived for a range of tsunami sizes striking a given coastline within a 1,000 year period. Note that in that paper tsunami height is measured just before the wave reaches the shore rather than run-up height. They assess the tsunami risk for a generic coastline and for the coastal cities San Francisco, New York, Tokyo, Hilo Harbour (Hawaii), Perth and Sydney.
  
  The estimates derived above indicate considerably less risk from an asteroid-generated tsunami than that derived by Ward and Asphaug. For example, they estimate the risk of a 10m tsunami inundating a generic coastline (with a semi-circular "target area" of ocean having is radius of 6,000km) is 1.1% in 1,000 years, equivalent to one event every 91,000 years and about one tenth of the risk estimated above.
  
  The main differences are likely to arise from assumptions about initial wave size and dispersion.
  
  Comparison with other asteroid impact risks
  
  In effect, the above analysis refers to risk of being caught in a region of direct devastation (being within the "blast area") compared with being within an area inundated by a tsunami. In the case of an impact by a large asteroid (diameter 2km or more) it has been estimated that 25% of the human population would die - mainly from indirect effects, such as starvation. This type of event is thought to occur with an average interval of 1 million years. The annual risk of dying in such an event is therefore about 1 in 4 million, which is similar to the tsunami risk for a location with a run-up factor of 5 (1 in 3 million).
  
  Maybe it's not all bad news!
  
  
  Simulation of tsunami generated by Eltanin impact near Chile.​
  
  
  Extract from animation by Dr C Mader.​
  
  
  
  In some circumstances an ocean impact might even be less hazardous to mankind than a land impact because less debris will be thrown into the atmosphere and indirect effects might be reduced. For example, it has been noted by Mader (1998) that the Eltanin impact by a large asteroid (estimates range from 1km to 4km) into the ocean near Chile some 2 million years ago did not create a crater on the seabed and apparently did not result in mass extinction. Contemplate what could have happened if the object had struck a slightly more northerly latitude and a few hours earlier - perhaps continental Africa would have been the target. Would Australopithecus, such as "Lucy", have survived? (Update: maybe it wasn't so benign - see this ABC News item about primate extinctions)
  Update 15 Feb 02: Steve Ward provided this dramatic graphic of the Eltanin impact (right click and View for a higher resolution).
  
  
  
  Conclusion
  This tentative analysis suggests that the risk from asteroid tsunami has been substantially overstated - particularly in popular books about asteroid impacts with Earth. For typical coastal regions the risk of dying from an asteroid-generated tsunami is probably no greater than that of dying from the indirect effects of a large asteroid striking the Earth.
  For some coastal regions with unusual vulnerability to tsunami the risk of dying from asteroid-generated tsunami may be several times greater than that of dying from other asteroid-related causes. For these highly vulnerable areas the typical interval between asteroid tsunami events is likely to be about 200,000 years - assuming that impacts are randomly distributed in time.
  
  There is considerable uncertainty about most of the "input values" used in these estimates. Also it is possible that impacts are not randomly distributed in time (Steel et al, 1995) and the Earth may be subjected to a barrage of small asteroids (or comet fragments) from time to time. This may have happened over the past few thousand years and could be a source of some of the tsunami that appear to have struck Australia during this period. Until we better understand the impact threat, there is no cause for complacency over the long intervals derived above. Finally, it is stressed that the run-up factor is not the sole issue in determining the destruction caused by a tsunami.
  References
  Crawford D.A. and Mader C.L. (1998) "Modeling asteroid impact and tsunami", Science of Tsunami Hazards, Vol 16, No.1.
  Hills J.G. and Goda M.P (1998a) "Tsunami from asteroid and comet impacts: the vulnerability of Europe",Science of Tsunami Hazards, Vol 16, No.1.
  
  Hills J.G. and Goda M.P (1998b) "Damage from the impacts of small asteroids", J Planetary and Space Science, Elsevier Science,( available in PDF format )
  
  Mader C.L. (1998) "Modeling the Eltanin asteroid impact", Science of Tsunami Hazards, Vol 16, No.1.
  
  Morrison D. and Chapman C. 1995 "The Biospheric Hazard of Large Impact". Proceedings of Planetary Defense Workshop.
  
  Nott J. and Bryant E. (1999) "PALEOTSUNAMIS ALONG THE AUSTRALIAN COAST", Proceedings of the Tsunami Symposium,(temporary link), The Tsunami Society, May 1999.
  
  Rynn J. and Davidson J.(1999) "CONTEMPORARY ASSESSMENT OF TSUNAMI RISK AND IMPLICATIONS FOR EARLY WARNINGS FOR AUSTRALIA AND ITS ISLAND TERRITORIES", Proceedings of the Tsunami Symposium,(temporary link), The Tsunami Society, May 1999.
  
  Steel D. (1995) Rogue Asteroids and Doomsday Comets, John Wiley & Sons
  
  Steel D., Asher D., Napier W. and Clube S. (1995) "Are impacts correlated in time?" Hazards due to comets and asteroids,
  
  Ward S.N. and Asphaug E. (1999) "Asteroid impact tsunami: a probabilistic hazard assessment", Icarus, 1999 (preprint). Summary in PDF format
  
  Yabushita S (1997) "On the possible hazard on the major cities caused by asteroid impact in the Pacific Ocean - II", Earth, Moon and Planets. 76 (1/2):117-121.
  
  R.Young R.W.,Bryant E.,Price D. and Spassov E. (1996) "The imprint of tsunami in quaternary coastal sediments of Southeastern Australia"
  website http://wwwrses.anu.edu.au/~edelvays/tsunami1.html

 

[Cosmos]

Good opportunity to look for more of these chevron's as Randall suggests.

By the way, chevrons are just on „proxy“ that scientist and geologists use to determine water flooding among many other things like current ripples, potholes, watermarks and boulders that are carried and deposited, depending on many complex factors, like the slope direction the water is flowing, the velocity, the amount of water that is transported, the surrounding land features, the amount and density of material the flood is eroding and carrying with it etc. as Randall points out. Within one type of flood event (no matter the size) you can usually see most of those features present in a scalable fashion. For example, at one spot the water is flowing slower (in a wide and flat non constricting area for example) while in another spot right besides it, it is flowing fast (in a restricted channel for example). Depending on the amount of water it carries and the landscape it is flowing on, it can also create natural dam like features that hold huge amounts of waters for hours, days and even weeks (during the mega floods at some places at the end of the last ice age for example) before it finally drains of, that then can create high watermarks on surrounding hills and mountains.

You can look at a small local river for example and see all of those signs of small scale flood events, that were many orders of magnitude bigger in scale in mega floods in the past. Here again you can see the "scale invariance" phenomena, where a small pattern of flooding is repeated in a much bigger scale and pattern in big floods. Also, in the case of tsunamis, usually (as we have seen in Indonesian Christmas tsunami in 2004 for example) there are several wave regimes at play. The first retreat of the ocean and the consequent onrush of the first wave waters is not as devastating and big as the second retreat an onrush.

It is a very complex phenomenon. So the chevrons you can see for the c.a. 5,000 before present event, on the coastlines surrounding the Indian ocean, is just one feature of that flood, which could likely mean that the water itself was spread over a much wider and higher area inland, in which other (for example slower) water features are present that can't be seen so easily from satellite images, especially after 5000 years.

Edit: Spelling