7.7 Earthquake Strikes British Columbia

[G-Man]

Terry Biddlecombe and others who reside in B.C., please let us know how you are fairing!
7.7 is a huge earthquake capable of severe damage.

Tsunami warning issued after 7.7 earthquake strikes British Columbia
Published October 27, 2012
Associated Press

http://www.foxnews.com/world/2012/10/27/tsunami-warning-issued-after-77-earthquake-strikes-british-columbia/#ixzz2AZMzCSYY

[HarrySmith]

Terry is not at home right now. He is on a cruise ship, not in that area. He also has limited, and expensive, internet access.

[TelePlay]

AP Update at 11 pm PST:

"ANCHORAGE, Alaska (AP) — A tsunami warning for southern Alaska and northern British Columbia has been downgraded to an advisory, while a warning has been issued for Hawaii.

In addition, the West Coast and Alaska Tsunami Warning Center says parts of coastal Oregon and northern California have been placed under a tsunami advisory.

The alerts came after the U.S. Geological Survey said the 7.7-magnitude earthquake hit in the Queen Charlotte Islands area Saturday night.

A tsunami warning means an area is likely to be hit by a wave, while an advisory means an area could be hit.

A small tsunami was barely noticeable in Craig, Alaska, where a four-inch wave was recorded."

Seems like a false alarm on the big wave. Hopefully, the small number of people who live on the island didn't get hit with too much damage if any. The media is once again really looking for someting, a major distraction, to top what happened in Benghazi 3 weeks ago. They have a hurricane in the Atlantic and now this earthquake with 13 aftershocks in the northern Pacific, both of which are non-stories given the magnitude of what happened in Benghazi.

As usual, the ring of fire plate is constantly active and if I lived in southern California, I be a bit more worried after this one. Here's a great resource of active earthquakes.

http://earthquake.usgs.gov/earthquakes/map/

[DavePEI]

CNN is now reporting the following: "The tsunami warning for Hawaii has been canceled.  A tsunami advisory is now in effect.

A tsunami advisory indicates that strong currents or waves that are dangerous to those in or very near the water are expected, but significant inundation is not expected."

We should all still be concerned for Terry - after all, he is on a boat in the Pacific. However, waves are much smaller than originally forecast, so I am sure a vessel the size of the one Terry is on, wouldn't be affected to any extent.

I have no idea what procedures are in place for cruise ships in the path of a tsunami - I would imagine the most important thing would be to keep as far from shore as possible to avoid the amplification of a tsunami's waves when they hit the shore.

Despite the magnitude of the earthquake (magnitude 7.7), little damage in BC has been reported so far. The earthquake hit the Queen Charlotte Islands off the BC coast, and even there, here is no sizeable damage reported.

There have been a number of smaller aftershocks, but it looks as though the worst is over. I guess this just serves as a reminder of the dangers to those on the Pacific rim/Ring of Firefrom geological activity.

The next concern will be the possibility of a superstorm created when Hurricane Sandy in the areas in its path. Currently, it looks as though PEI will be spared, but there could be severe consequences for those in the path from  North Carolina and Maine, and stretching from there into the into the St. Lawrence Valley of Ontario. Anyone living in the area should keep up with the news, and stay prepared.

We have a lot of members who could be affected. Take care, and stay safe. Each and every member matters to us all!

Dave

[JohnInWI]

I think this earthquake may be due to fracking in the area.  An area of Texas has had numerous earthquakes lately where there used to be none.  There is fracking in that area as well.

[DavePEI]

I think this earthquake may be due to fracking in the area.  An area of Texas has had numerous earthquakes lately where there used to be none.  There is fracking in that area as well.

I know it is popular to blame everything on fracking, and I don't approve of it either, and the process has caused a lot of problems in many areas - it is a dangerous process, but the Queen Charlotte Islands are in a traditional earthquake zone, part of the "Ring of Fire"", and they have had many recorded earthquakes through the years, including a magnitude 8.1 quake in 1949. The area is on the Queen Charlotte Fault. It also has suffered quakes in 1929, 1970, 2008, and probably others I have missed.

http://en.wikipedia.org/wiki/List_of_earthquakes_in_Canada

Dave

[twocvbloke]

They tried Fracking in Blackpool, Lancashire, and they started getting tremors in places around where they were doing the fracking process, they tried to blame other reasons for it, but you can't deny that the tremors started around the same time as the fracking, and then stopped when they stopped....

I know that natural gas supplies are low, and getting lower, but, trashing the ground (and houses & businesses ontop of the ground) to get at little tiny pockets of the stuff just isn't worth it in my books, after all, the stuff we flush down the toilet can be used to make natural gas, and that doesn't cause earthquakes and tremors....

[TelePlay]

Yes, Dave, you are right. There are many plates which make up the earth's crust and they are all moving. The North American plate is sliding sideways against the Pacific plate and the Pacific plate is pushing against the Eurasian plate.

Brand new earth crust is formed in the middle of the Atlantic pushing the African and Eurasian plates against the Pacific plates.

There are many smaller plates which all get pressured in the mix. There is a very small plate right their in the BC Islands (Juan de Fuca Plate) that by its existence is moving under the Pacific plate.

As such, the pressure or force of one plate against another builds up over many years until the accumulated pressure is greater than the two parts of the crust preventing movement and the pieces move a small amount quite quickly. The result, an earthquake.

In California, the pressure is a slipping movement so when the movement happens, roads and rail road tracks all of a sudden are disjointed by many feet.

Regardless of how the plates give way under pressure, the resultant earthquake rattles everything on the surface and damage can be done to buildings that can not withstand the shaking.

After shocks are smaller parts of the crust settling after the major parts give way.

The movement of the pacific plate can be seen by looking at the Hawaiian Islands which were created by lava flow from on thin part of the earth's crust over many, many years. The movement is to the northwest so the biggest islands were the last ones to be formed. There is a new island rising to the surface southeast of the last current island and will surface in a few hundred years.

Plate tectonics is a fascinating science within geology and covers both earthquakes and volcanoes. Here's one of many sites that explain plate tectonics.

http://serc.carleton.edu/NAGTWorkshops/geophysics/visualizations/PTMovements.html

With all that said, fracking can be the straw that breaks the back, that triggers a plate, or two plates, that are building up pressure but on the good side, the fracking is triggering the earthquake well before it would normally happen meaning the magnitude of the earthquake would be less than if left to build to full pressure and release naturally.  So, fracking might actually be reducing damage and devastation from naturally occurring earthquakes.

And, keep in mind that there are hundreds of earthquakes all over the world every week, only the big ones get reported.

http://earthquake.usgs.gov/earthquakes/map/

According to the USGS, there were 1489 earthquakes within the past 7 days of all magnitudes around the world, all on plate boundaries.

[DavePEI]

"The October 28th, 2012 (October 27 at the location of the epicenter) M 7.7 earthquake south of Masset, Canada, occurred as a result of oblique-thrust faulting near the plate boundary between the Pacific and North America plates. At the location of this event, the Pacific plate moves approximately north-northwest with respect to the North America plate at a rate of approximately 50 mm/yr.

This earthquake is likely associated with relative motion across the Queen Charlotte fault system offshore of British Columbia, Canada. Studies of tectonics in this region suggest plate motions are taken up by strike slip faulting parallel to the plate boundary, accompanied by lesser amounts of thrust motion to accommodate the oblique nature of the plate motion vector between the two plates with respect to the orientation of the main plate boundary fault structure. This oblique component of plate motion may involve either underthrusting of the western edge of the Pacific Plate beneath North America, or be taken up on crustal faults within the North America plate. The October 28th earthquake is consistent with either scenario. Its rupture extended approximately 100-150 km along strike, along the shallow extent of the source fault. Slip amounts reached approximately 5m, in a patch to the south of the epicenter. Aftershocks delineate the rupture well, as shown here.

This region of the Pacific:North America plate boundary has hosted 7 earthquakes of magnitude 6 or greater over the past 40 years – the largest of which was a M 6.6 earthquake in 2009, 80 km to the south east of the 2012 earthquake. In 1949, a M 8.1 earthquake occurred closer to the Pacific:North America plate boundary, likely as a result of strike-slip faulting, approximately 100 km northwest of the October 28th earthquake, near the northern extent of Haida Gwaii region (formerly Queen Charlotte Islands)."

http://earthquake.usgs.gov/earthquakes/eventpage/usb000df7n#summary

As far as I can see, the closest fracking to this area is in North east BC, hundreds of KM away from the Queen Charlotte Islands, where it is being blamed for some local seismic occurrences, but it is unlikely to have any affect on this quake which occurred on the other side of what is a huge province in what traditionally was considered a seismic hot spot.

We can all be thankful that despite the magnitude of the quake, little damage was done, thanks in part to the type of construction in the area, wood framed homes which are flexible, and to the horizontal slip nature of the quake.  Fortunately, also, this played a part in reducing the dangers of Tsunamis being created by the quake. A vertical movement would have been more likely to have created a significant tsunami.

I want to point out that I am not an expert on tectonic movement, but I have had an interest in the subject ever since the Plaster Rock, NB quake in the early 80s, which, despite our distance from it, was enough to wake both Linda and I up when it hit. When we awoke, I turned on the radio, as was my practice at the time, and heard the first reports of the quake. Since then, I have read everything I could on the subject.

Sandy:

More of a concern now, is what Hurricane Sandy's effect on the East Coast could have on Eastern North America, particularly if it does merge with weather fronts to produce a super storm as feared. Thankfully, for now, my area is likely to be spared if the storm goes the way it is forecast, but it affects one of the most populated areas in North America.

For those living in affected areas, stay on top of local warnings, and stay safe.

Dave

[TelePlay]

Thank you Dave.

I thought you were an expert geologist but at your disclaimer, I see we are both hobbyists in that area. I would like to add that a lot of fracking has been going on in both North and South Dakota in the states over at least the past year and NO earthquakes were the result of that activity. Maybe fracking on a fault line could contribute but the amount of energy involved before and during an earthquake greatly exceeds the very small amount of energy used in any one or combination of many fracking explosions.

It is a fascinating science, plate tectonics that is. They have underwater video of lava boiling up from the earth from Greenland through the Atlantic where the two plates are pulling apart giving lava free access to the surface. The lava tubes formed in the cold water look like piles of spaghetti. On the other end, the Rocky Mountains were formed by plate collision over many years and the Flat Irons between Denver and Boulder Colorado show the thrusting of flat sea bed into a horizontal position by these geological events, and Denver is a mile above sea level. It is a fascinating scene indeed.

[DavePEI]

Yes, just a hobbiest... Its been an interest of mine since 1982's Plaster Rock quake. In an area where so little seismic activity was suspected, that was a tremendously interesting event. Phones still remain #1, though  

Actually, BC is one place where one can demonstrate a relationship between fracking and earthquakes. But not in the Queen Charlotte Islands - over a thousand miles away in the extreme north eastern end of the province where a spate of small earthquakes began shortly after fracking began,,,

See:

http://tinyurl.com/9pa9gh3

Dave

[twocvbloke]

You know, I just recalled the very minor quake we got in 2007, only a 2.5, originated somewhere under Manchester, Lancashire. I was awake during the night when it happened, and boy did it frighten the life out of me, the sound I thought was a large heavy goods truck rolling down the street (very uncommon, especially at night!!), but then everything started shaking, kind of like the shaking that you got on old driving game arcade machines, that's when I started panicking, cos being a Brit on a relatively stable plate, you don't normally expect something like that, once it went quiet I tried calling 999 to report it, but their lines were busy (hardly surprising), wasn't until the next day I found out it was a proper quake, even if it was a tiddler in comparison to others...

Mostly no damage, but, my bedroom window suddenly developed a crack in it afterwards, so, I think that may have loosened the (very old stone) house a little... 

I'd hate to be in a full on proper earthquake though, seeing CCTV and home video footage from the Japan quake was pretty scary stuff, with tall buildings swaying, pools being sloshed back and forth, cracks in the ground opening and closing, and of course, the devastating Tsunami that happened afterwards, makes me glad what we get is usually a slight vibration...

[AE_Collector]

Hi Everyone:

Well actually, the ship sunk and I've been lost at sea for the last month but finally I was picked up by some Hawaiin's in a Canoe. After a few Mai-Tai's and a couple of days at the beach I'm "ready to go"!

The Captain of the Cruise ship (Celebrity Milennium) had to go on the PA system throughout the ship to tell everyone what had happened and it was obvious that he really didn't want to have to worry everyone when in all liklihood there was nothing to worry about. As Dave mentioned, we were still at Sea but only about 10 hours out of Hilo Hawaii where we arrived the next morning. Nothing happened at all but they sure took it seriously throughout Hawaii. Tsunami Sirens went and all people close tothe coast were evacuated to higher land for several hours until the thread came and went. Waves of varying heights up to no more than 2 feet were recorded at various locations.

Thanks everyone for your concern, just another adventure for us.

Terry