Disturbance 98L probably no threat to land

By: Dr. Jeff Masters , 1:46 PM GMT on September 18, 2009

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A tropical disturbance (98L), is located midway between Africa and the Lesser Antilles Islands. This disturbance has a well-defined surface circulation, and has developed a modest amount of heavy thunderstorm activity overnight. This morning's QuikSCAT pass (Figure 1) shows a complete, circular wind pattern around the low pressure center of 98L, but top winds were only 25 mph. Wind shear is moderate, about 15 knots, and Sea Surface Temperatures are 28°C, which is about 2°C above the 26°C threshold needed to support a tropical cyclone. There is a large amount of dry air to the north and west of 98L, and this dry air is interfering with development.

The global computer models predict differing amounts of wind shear in the path of 98L as it moves west-northwest at 10 mph over the next three days. The ECMWF, GFS, and UKMET models do not develop 98L, while the NOGAPS, GFDL, and HWRF do. The models that do develop 98L predict that a strong trough of low pressure will turn 98L to the northwest and then north beginning on Monday, with the result that 98L misses the Lesser Antilles Islands by at least 500 miles. Given the moderate or higher wind shear in 98L's path, and dry air to the northwest, the system should develop only slowly. NHC is giving 98L a medium (30 - 50%) chance of developing into a tropical depression by Sunday. At this time, it does not appear that 98L will ever threaten any land areas.

The remains of Hurricane Fred are still spinning away, near 25N 66W, about 900 miles east of Florida. Wind shear is 20 knots, which is marginal for development, and there is very dry air surrounding ex-Fred on all sides. None of the computer models develop ex-Fred, and it will have a tough time regenerating with so much dry air and wind shear. The remains of Fred should move over Florida Monday night or Tuesday morning.


Figure 1. Morning QuickSCAT image of the Atlantic, showing the well-defined surface circulation of disturbance 98L. Image credit: NOAA/NESDIS.

One year anniversary of Hurricane Ike
I've been focusing this week on the 20th anniversary of Hurricane Hugo, but we also passed the one year anniversary of Hurricane Ike. Many areas along the Texas and Louisiana coast affected by Ike have fully recovered, but recovery efforts will still take many more years in other areas. In Galveston, which suffered $3.2 billion in damage, 75% of the businesses have reopened, and 95% of the population has returned. Boston.com has posted a very nice series of clickable images that show before and after scenes of some of the areas that have recovered from Hurricane Ike.

Ike washed away huge sections of beach and dunes that helped protect the Texas coast from more serious damage, and this week the state legislature approved $135 million in funds to help replace these critical natural protection systems. The restored beaches will probably last ten years, barring another strike by a hurricane of Ike's stature. Texas considers two-thirds of its 367-mile shoreline to be critically eroding, which it defines as a historical rate of more than 2 feet a year. Much of this erosion can be blamed on sea level rise. Global sea level rose seven inches over the past century, and is expected to rise at least that much over the coming century.


Figure 2. Villagers in Haiti plant one of their "Million Tree Campaign" trees. Image credit: Lambi Fund of Haiti.

Hurricane relief donations
There hasn't been a need for new hurricane-related disaster relief efforts this year, in stark contrast to 2008. However, the charities we rely on to provide disaster relief still require funds to operate in quiet years, and I encourage you to consider a donation at this time to one of my two favorite disaster relief charities. Portlight.org, which was very effective at helping out isolated, under-served communities in the wake of Hurricane Ike, is committed to raising $12,000 to purchase and outfit a mobile kitchen. This kitchen will be capable of feeding up to 2,000 people two hot meals per day in post-disaster situations. The Lambi Fund of Haiti has launched its "Million Tree Campaign", which aims to use local labor to plant a million trees over the next three years along severely deforested slopes in Haiti. Both of these charities wrote to me several times last year about the stunning generosity readers of this blog showed with their donations. Thanks!

Twenty years ago today
As Hurricane Hugo approached the U.S. Virgin Islands in the early morning hours of September 18, 1989, the storm slowed down to 10 mph. The slower speed allowed Hugo to punish the island of St. Croix with the worst beating of any location along the hurricane's destructive path. At 2am local time on September 18, 1989, Hurricane Hugo's eyewall struck St. Croix, bringing incredibly ferocious Category 4 winds, sustained at 140 mph. The hurricane's gusts were remarkably violent, and many residents witnessed tornado-like vorticies barreling across the island as the hurricane raged about them. A storm surge of 2 - 3 feet, topped by battering waves 20 - 23 feet high, assaulted the coast, adding to the destruction. Wunderground member Mike Steers wrote me to describe his experience on St. Croix: "Hugo was incredible. Many vortexes came in that night. The roar and intensity of the winds that night were incredible. When the eyewall came over, we were forced to take refuge in the bathroom as the rest of the house came apart. The pressure was so low outside the house that all of the water was sucked out of the toilet and an air draft was created through the toilet. Just when I thought it was as bad as it would get, the intensity of it all dialed up even higher. Dozens and dozens of times, my ears would violently pop due to rapid pressure changes. The next morning, of course, the devastation was unbelievable. In my front yard was a 18-foot boat with an outboard on it, that had been picked up from a marina two miles away. I had lost my house, and job, the Seaplane company I was a pilot for. After a couple months, I had to leave everything behind. In some respects, after 20 years, there an many aspects of the society that have yet to recover". Two people were killed on St. Croix, 80 injured, and 90% of the buildings were damaged or destroyed. Damage estimates for St. Croix were astronomical, over $1 billion, and the island's entire infrastructure was virtually wiped out. Six weeks after the hurricane, only 25% of the public roads had been cleared, and only 25% of the island had power.


Figure 3. GOES visible satellite image of Hurricane Hugo taken on September 18, 1989. Note the lack of cloud cover on the hurricane's southwest side, indicating that strong upper-level winds from the southwest were likely creating wind shear, weakening the storm. Image credit: Google Earth rendition of the NOAA HURSAT data base.

As Hugo departed St. Croix, strong upper-level winds from the southwest created wind shear that weakened the storm to a Category 3 hurricane with 130 mph winds. The upper level winds also caused Hugo to accelerate to 15 mph and turn more northwest. The eye passed over Puerto Rico's Vieques Island at 8am and over Fajardo on the extreme northeastern tip of Puerto Rico at 9am. On Culebra Island, an island twelve miles east of Fajardo, a gust to 170 mph was recorded by the ship Night Cap in the main harbor. The south-facing harbor received sustained southerly winds in excess of 120 mph for several hours as Hugo roared by to the south. The resulting wave "set-up" created a storm surge in excess of 13 feet in the supposedly hurricane-proof harbor. A large portion of the Caribbean's charter boat fleet, some 200 boats, was sheltering in Culebra's harbor, and 136 of these boats were badly damaged or sunk. Over 80% of the wooden structures on both Culebra and Vieques were destroyed.


Figure 4. Damage on St. Croix (two top photos), Culebra Island (bottom right), and Puerto Rico's Roosevelt Roads Navy Base (bottom left), after Hurricane Hugo. Image credit: NOAA Photo Library.

Along the northeastern coast of Puerto Rico, waves up to ten feet high riding on top of a 3 - 4 foot storm surge caused severe coastal flooding of low-lying areas. Hugo's winds tore into Puerto Rico's El Yunque rainforest, downing thousands of trees. The agricultural sector was devastated, with nearly all of the island's banana and coffee crops wiped out. Twelve deaths in Puerto Rico were attributed to Hugo, six of which occurred in the southern city of Guayama where some residents were electrocuted by downed power lines. Nearly 28,000 people were left homeless by the storm, and damage to the island exceeded $1 billion.

Storm chaser Michael Laca was at Luquillo Beach on the northeast shore of Puerto Rico, and has posted a remarkable 28-minute video on YouTube of Hurricane Hugo footage.

Jeff Masters

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Member Since: June 28, 2006 Posts: 25 Comments: 8360
zombie fred looks more like a open wave right now
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Quoting BDAwx:

Link to concentric eyewalls in Choi-Wan


thats really cool, thanks!
Member Since: June 28, 2006 Posts: 25 Comments: 8360
789. BDAwx
Quoting tornadodude:


cool, can you give us a link or an image please? thank ya

Link to concentric eyewalls in Choi-Wan
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Quoting Grothar:


Thanks Cane? I am watching is closely because I live in Lauderdale. A TS is nothing more that a nuisance most of the time.



I agree but, a TS this time of year in those waters bears extra attention.
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Quoting rwdobson:


you're probably right...i'm more of a chemist so I studied limestone dissolution a lot in grad school...earthquakes not so much.


Well, don't discount the effect of compaction and force dissolution through compaction of the "holes" in the limestone...the effect should be substantial; the rolling will cause some serious damage in the outlying areas. The odd thing about the studies? Damage in central Missouri on the Ozark Platerau will be minimal; my hometown of Fulton woudl feel , if mamory serves, a 2.5 in the vent of a 7.5 event. Illinois and Western Tennessee, on the other hand, will get to find out how to do the twist
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Quoting BurnedAfterPosting:
where is the model guidance that shows the coordinates from the BAM guidance but also shows the intensity

I was just wondering what the models are saying in terms of strength of Ex Fred


This should help.. Not sure I agree with it being that strong, but the Gulf Stream is very warm and shear will be lower by then.

Member Since: July 1, 2008 Posts: 13 Comments: 7432
Quoting TheCaneWhisperer:


IMO, track will be determined by 2 things. Strength and orientation of the Ridge. Fred will be under the ridge (Not riding the edge) so I don't think strength of the storm is going to matter much.


Thanks Cane? I am watching is closely because I live in Lauderdale. A TS is nothing more that a nuisance most of the time.
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Hurricane and Grothar, do you guys mind getting on Tropics Chat (without speaking German) please?
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Looks like the 18z NAM shows Fred getting to the Bahamas then tightening up a bit just before landfall. A "sleeper", maybe?

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Quoting TheCaneWhisperer:


IMO, track will be determined by 2 things. Strength and orientation of the Ridge. Fred will be under the ridge (Not riding the edge) so I don't think strength of the storm is going to matter much.


You can see this analyzing the BAMM suite. The BAMMD is for deep storms and is the southern most of the package. What I gather from that is they have different degrees of ridge strength (How fast it builds in) and different orientations and nothing to do with strength.
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Updated intensity on Fred. LOL at the OFCI. Wouldn't want to go out on a limb, now.

Link
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Quoting Floodman:


Actually, based on the fracture studies, outlier events in the 5-6 range occur singularly quite frequently; the events I'm talking about are more like the "storm" in 1811-12...I grew up in central MO and have been in that area quite a bit; you can still see the sand blows and the road cuts on I55 show numerous fracture zones


oh ok, I see what you mean now, could this be a precursor to a larger event?
Member Since: June 28, 2006 Posts: 25 Comments: 8360
779. HadesGodWyvern (Mod)
National Hurricane Center
Tropical Cyclone Warning #11
TROPICAL CYCLONE MARTY (EP162009)
21:00 PM UTC September 18 2009
=================================

At 18:00 PM UTC, Tropical Storm Marty (1004 hPa) located at 21.1N 115.2W or 315 NM west-southwest of the southern tip of Baja California Peninsula has sustained winds of 35 knots with gusts of 45 knots. The cyclone is reported as moving northwest at 6 knots.

Gale-Force Winds
================
60 NM from the center

Forecast and Intensity
====================
12 HRS: 21.7N 116.2W - 30 knots (Tropical Depression)
24 HRS: 22.4N 117.7W - 30 knots (Tropical Depression)
48 HRS: 22.6N 121.5W - 20 knots (Low Pressure Area)
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Quoting hydrus:
you sound like (doctor)Floodman, are you a geologist?


me?
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting Grothar:


Sorry I didn't get back sooner, but rwdobson is correct. The more cracks in the underlying layers, the more the energy is disrupted. Since a large quake would undoubtedly cause devastation, it would be felt in a smaller area. In a place such as Boston, even a small quake would be felt over a large area since they energy would have less resistance since there are fewer fractures in the earth on the east coast than the west coast. It doesn't necessarily mean there would be greater destruction, just the areas affected would be much larger. Look up the Boston Earthquake sometime and see the area which was affected.

Now back to FRED!!!


ok, gotcha, thanks
Member Since: June 28, 2006 Posts: 25 Comments: 8360
where is the model guidance that shows the coordinates from the BAM guidance but also shows the intensity

I was just wondering what the models are saying in terms of strength of Ex Fred
Quoting rwdobson:


you're probably right...i'm more of a chemist so I studied limestone dissolution a lot in grad school...earthquakes not so much.


well my peer mentor here at Purdue happens to be a geology professor, I suppose I can talk to him about this sometime
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting tornadodude:


the latest being a 5.2 in april of 2008


Actually, based on the fracture studies, outlier events in the 5-6 range occur singularly quite frequently; the events I'm talking about are more like the "storm" in 1811-12...I grew up in central MO and have been in that area quite a bit; you can still see the sand blows and the road cuts on I55 show numerous fracture zones
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Quoting tornadodude:


the latest being a 5.2 in april of 2008
you sound like (doctor)Floodman, are you a geologist?
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Quoting tornadodude:


ah, ok, thanks


Sorry I didn't get back sooner, but rwdobson is correct. The more cracks in the underlying layers, the more the energy is disrupted. Since a large quake would undoubtedly cause devastation, it would be felt in a smaller area. In a place such as Boston, even a small quake would be felt over a large area since they energy would have less resistance since there are fewer fractures in the earth on the east coast than the west coast. It doesn't necessarily mean there would be greater destruction, just the areas affected would be much larger. Look up the Boston Earthquake sometime and see the area which was affected.

Now back to FRED!!!
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Quoting Floodman:


From what I can gather, despite the fracturing a distinct "rolling" effect would occur and there would be some pretty fair damage...the issue with the New Madrid fault system is that historically (and some of this data comes from studying ancient fracture zones) an event of the magnitude of the 1811-12 event happens about every 5-600 years; smaller events in the 7.0 range on average about every 200 years


you're probably right...i'm more of a chemist so I studied limestone dissolution a lot in grad school...earthquakes not so much.
Member Since: June 12, 2002 Posts: 0 Comments: 1589
Fred...this time yesterday (Find it if you can lol)



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Quoting hydrus:
That was far better than mine. Have you looked at the low in the Caribbean lately?


we'll call them equal :)

and no, not really, what's it doing?
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting Grothar:


Then your opinion is actually in line with most of the others as well. It would appear now that even the Late-NHC may be thinking along the same lines. If the trough were to lift, it would follow that the track of 007L would also shift a little more. Would that be a correct assumption?


IMO, track will be determined by 2 things. Strength and orientation of the Ridge. Fred will be under the ridge (Not riding the edge) so I don't think strength of the storm is going to matter much.
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Quoting tornadodude:
once we had a cane named fred,

shear kicked his butt, so now he's dead,

a come back is possible, some have said,

to whom will the crow be fed?
That was far better than mine. Have you looked at the low in the Caribbean lately?
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Quoting Floodman:


From what I can gather, despite the fracturing a distinct "rolling" effect would occur and there would be some pretty fair damage...the issue with the New Madrid fault system is that historically (and some of this data comes from studying ancient fracture zones) an event of the magnitude of the 1811-12 event happens about every 5-600 years; smaller events in the 7.0 range on average about every 200 years


the latest being a 5.2 in april of 2008
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Looking at this loop...

Fred has gotten better organized over the past couple of days.
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Quoting homelesswanderer:


It's title is 8.0. I forgot who wrote it. I just tried to google it and looked on book seller sites but can't find it.


Darn that memory of mine. :( I'm sorry. It's called 8.4 by Peter Hernon.

I googled it the old fashioned way. Dug through my books. :)

Link
Member Since: August 15, 2008 Posts: 10 Comments: 3665
Quoting rwdobson:


hmm...limestone is usually fractured and riddled with caverns anyway...i would think it might actually dampen the earthquake waves. would probably open up quite a few sinkholes...


From what I can gather, despite the fracturing a distinct "rolling" effect would occur and there would be some pretty fair damage...the issue with the New Madrid fault system is that historically (and some of this data comes from studying ancient fracture zones) an event of the magnitude of the 1811-12 event happens about every 5-600 years; smaller events in the 7.0 range on average about every 200 years
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Quoting Grothar:


Fred is suffering?? What about us! We are suffering from overfrederization. This is more than "Nightmare on Elm Street".


try ctrl plus F and type Fred.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
once we had a cane named fred,

shear kicked his butt, so now he's dead,

a come back is possible, some have said,

to whom will the crow be fed?
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting Floodman:


The February 7th 1812 earthquake rang churchbells in Boston over 1300 miles away
Yeah, And just to imagine how hard a shaking it would take to ring that church bell.
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Quoting TheCaneWhisperer:


We'll according to my not so accurate GFS shear map about 12 to 18 hours.

My personal opinion now that the trough is lifting out is that shear will let up enough tomorrow morning for 07L to maintain what it's gained and it may just be enough to get it re classified tomorrow. If anything, it's very own floater.


Then your opinion is actually in line with most of the others as well. It would appear now that even the Late-NHC may be thinking along the same lines. If the trough were to lift, it would follow that the track of 007L would also shift a little more. Would that be a correct assumption?
Member Since: Posts: Comments:
Quoting TheCaneWhisperer:


We'll according to my not so accurate GFS shear map about 12 to 18 hours.

My personal opinion now that the trough is lifting out is that shear will let up enough tomorrow morning for 07L to maintain what it's gained and it may just be enough to get it re classified tomorrow. If anything, it's very own floater.


Plane is scheduled for tomorrow so we should know for sure. I think they will fly it as they haven't been up much this year and it's a pretty safe bet it's going to effect somewhere along the coast, no dis-respect to the Bahamians.
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@748

Awesome work...
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Quoting tropics21:
he's using a walker kinda shuffeling around


nice
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Quoting Grothar:


Hey Cane, any idea when the conditions will be more favorable, or conducive for a little more development on 007L. There seems to be agreement then disagreement. Any thoughts.


We'll according to my not so accurate GFS shear map about 12 to 18 hours.

My personal opinion now that the trough is lifting out is that shear will let up enough tomorrow morning for 07L to maintain what it's gained and it may just be enough to get it re classified tomorrow. If anything, it's very own floater.
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Quoting tornadodude:


LMAO!

awesome!
thank you...I want Fred to go away....The End.
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Quoting rwdobson:


hmm...limestone is usually fractured and riddled with caverns anyway...i would think it might actually dampen the earthquake waves. would probably open up quite a few sinkholes...


ah, ok, thanks
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting TheCaneWhisperer:


That's the trough that was supposed to move east not get stuck.

So, it was supposed to have an effect but, now it's not. The HP ridge on the east coast will do the driving.


Hey Cane, any idea when the conditions will be more favorable, or conducive for a little more development on 007L. There seems to be agreement then disagreement. Any thoughts.
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26N and 70.8W 9/19......flight plan in place*** Fred not dead!!
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Quoting tornadodude:


so here in Indiana, where we have a ton of limestone, would the limestone magnify the earthquake's effect?


hmm...limestone is usually fractured and riddled with caverns anyway...i would think it might actually dampen the earthquake waves. would probably open up quite a few sinkholes...
Member Since: June 12, 2002 Posts: 0 Comments: 1589
Quoting hydrus:
Fred is dead-
so they say-
He may regenerate-
to my dismay-
if He comes-
and wrecks my house-
I will get loaded-
with my spouse.


LMAO!

awesome!
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting holynova:
Quoting hydrus:
He is alive, he is dead, he is open, he is closed......yyyaaaawwwwnnn!



Fred is: Schizofredic

LOL too funny!!!!!
Fred is dead-
so they say-
He may regenerate-
to my dismay-
if He comes-
and wrecks my house-
I will get loaded-
with my spouse.
Member Since: Posts: Comments:
Have a great evening everyone!

Wait and watch still with ex-Fred

+ nice low level circulation
+ shear to decrease somewhat for at least 12 hours tomorrow
+heading to warm waters

-Dry Air
-Shear Currently and then some westerlies again possible close to landfall


Guess we'll just have to wait and watch!
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Quoting Floodman:


Everyone wants to talk about the San Andreas and yes, when it goes with a "big one" it's pretty devestatiing, but the New Madrid fault zone and the surrounding deep faults are over 3 miles down, causing far reaching vibration...cities across the midwest will see damage but STL and Memphis will see the worst of it


No argument there! Quite familiar with the scenarios. Damage would be enormous! Some do not realize the true danger.
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Quoting Grothar:


That is 100% true, but liquifaction usually occurs in smaller areas. The fear is that when a moderate earthquake goes through hard bedrock, the tremors are felt for much longer distances and can cause greater damage. Too much to put in here, but look up the scenarios on a quake in Boston or New York and it shall give you an idea of the rationale. It truly is interesting.


so here in Indiana, where we have a ton of limestone, would the limestone magnify the earthquake's effect?
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting SunnyDaysFla:


May I ask the name of the book? Thanks


It's title is 8.0. I forgot who wrote it. I just tried to google it and looked on book seller sites but can't find it.
Member Since: August 15, 2008 Posts: 10 Comments: 3665
Quoting Seasidecove:
Hey the New Orleans NWS, says that another low pressure cell will be moving out of the Plain States to reinforce the current Low over the Lower MS Valley, Keeping us in the Washing Machine for the next 5 days...will this have any effect on Fred, as to it's eventual track..or no?


That's the trough that was supposed to move east not get stuck.

So, it was supposed to have an effect but, now it's not. The HP ridge on the east coast will do the driving.
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Quoting jeffs713:

The Marina district in the 1989 San Francisco quake is a prime example of what liquefaction does in a quake. And that was a 7.0. A 7.8 is roughly 15-20 times more powerful (in terms of energy released).


That is 100% true, but liquifaction usually occurs in smaller areas. The fear is that when a moderate earthquake goes through hard bedrock, the tremors are felt for much longer distances and can cause greater damage. Too much to put in here, but look up the scenarios on a quake in Boston or New York and it shall give you an idea of the rationale. It truly is interesting.
Member Since: Posts: Comments:

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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