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Washington state residents rattled by Mount St. Helens tremors

Washington state residents rattled by Mount St. Helens tremors

Mount St. Helens is rumbling again, but it’s not the volcano that worries Washington state seismologists the most.

A 3.9-magnitude jolt Wednesday morning, about 11 km northeast of the volcano, was the strongest tremor in the seismically active area since 1981. It was followed by a swarm of up to 150 smaller earthquakes.

In 1980, an eruption blew out the side of the volcano, killing 57 people and devastating the landscape. Cascades of water, mud, and rock raged down valleys and knocked down forests.

But the latest quakes do not signal that the volcano is moving closer to another eruption, seismologist Seth Moran told On the Island host Gregor Craigie.

“There are earthquakes that are occurring at Mount St. Helens kind of continuously,” said Moran, who is a seismologist and scientist-in-charge at the United States Geological Survey’s Cascades Volcano Observatory.

The most hazardous volcano in Washington state is considered by seismologists to be Mount Rainier, where volcanic mud flows, called lahars, roar down the Puyallup River drainage system every 500 to 1,000 years.

“That’s a long time from a humanity perspective, but from a geologic perspective that’s pretty frequent and a really good reason for believing it’s going to happen again,” Moran said.

Tens of thousands of people are in the path of a large lahar, including the Washington communities of Orting, Sumner and Puyallup. In a worst-case scenario the lahar could reach Tacoma, though related flooding is more likely to affect the city.

Moran said the lahar detection system set up two decades ago by Pierce County with USGS assistance is now old technology, but it can be updated to provide more effective and earlier warning for the “bump in the night” event that could give residents as little as 45 minutes to escape to safety.

“We’ve done studies of the volcano itself and there are parts of the volcano, of the cone, that we know are somewhat unstable and have the potential to let loose again with one of these things,” Moran said. “The likely scenario is it wouldn’t happen unless the volcano is in a state of unrest or eruption.”

While the recent earthquake close to Mount St. Helens might seem alarming, Moran said it is not cause for concern.

If magma was moving in the volcano, Moran said, “It would be different. We’ve seen Mount St. Helens wake up twice and in both cases it was pretty obvious what was happening in terms of how different things were or how different things quickly became.”

​When the volcano became active again in 2004, he said, the earthquakes started small and increased in strength and frequency over time instead of decreasing, as they have this week. There were also ground deformations and glacier cracks.

Source: http://www.cbc.ca/news/canada/british-columbia/st-helens-earthquakes-mt-rainer-lavar-mudflow-volcanoes-1.4473612

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Light earthquakes strike in northern B.C. and off Vancouver Island

An earthquake hit northern B.C. near Alaska and the Yukon at 4:10 p.m. today (December 18).

The quake was located on land at a depth of 10 kilometres (6 miles) and 53 kilometres (33 miles) northwest of Mosquito, Alaska, and 127 kilometres (78 miles) southwest of Whitehorse, Yukon.

The U.S. Geological Survey has listed it as a 4.1-magnitude event while Earthquakes Canada has listed it measured it as a 4.3-magnitude quake.

Both measurements of the seismic event fall within the light category on the Richter scale, which is stronger than a minor earthquake yet significant damage is unlikely.

Meanwhile, a light earthquake also struck offshore west of Vancouver Island on December 16 at 8:11 p.m.

The epicentre of the 4.2-magnitude quake was located 166 kilometres (103 miles) west of Port Hardy, at a depth of 10 kilometres (6 miles).

A few quakes have struck the area over the past few weeks. On December 5, a 4.0-magnitude quake occurred in the area between Haida Gwaii and Vancouver Island. Before that, a 4.5-magnitude quake struck offshore of Vancouver Island 174 kilometres west of Port Hardy on December 3.

Source: https://www.straight.com/news/1009376/light-earthquakes-strike-northern-bc-and-vancouver-island

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Old drawings could assist new earthquake plan at the B.C. Legislature

The imposing British Columbia Parliament Buildings have a fatal weakness: they could collapse in a major earthquake.

The legislature, as the buildings are more commonly known, was built long before modern seismic building codes were adopted. Engineers have identified its iconic dome above the centre block as being particularly vulnerable to damage.

Fixing the century-old structure would be expensive with past estimates pegging a retrofit at somewhere between $700 million and $900 million.

But now the Speaker and legislative officers are working on a proposal that could lead to the construction of a new seismically-robust back-up building.

Craig James, a legislative clerk, said such a plan could draw inspiration from a historic architect.

Francis Rattenbury gained fame in the early 1900’s for a number of landmark buildings, including the B.C. Parliament Buildings and the nearby Empress Hotel.

“One option that we have is to take one of Rattenbury’s drawings to replicate a portion of this building over there, which in looking at it would be spectacular,” said James.

The proposal would see the old brick armoury building that currently stands behind the legislature torn down to make way for a new building.

“That building would in some part replicate on a smaller scale this place,” James said. “But also a larger chamber could be built over there so that in the event that something did happen here and this place was unusable, perhaps we could use it.”

Of course, government does not need an ornate legislative assembly to function. And building a back-up legislative assembly would not be cheap, likely costing tens of millions of dollars. But James notes that is about one-tenth of the cost of retrofitting the legislature itself.

Gary Lenz, the sergeant-at-arms, says ensuring continuity of government and a rapid response to an emergency are important.

“We all form that linkage towards passing of bills and legislation, which is critical if there’s a major earthquake or there’s a major disaster in the province.”

Speaker Darryl Plecas said a new building would play a crucial role in an emergency, and would also make the eventual seismic upgrade of the legislature more feasible.

“We could really be helpful in two ways. One is we help ensure continuity of government because we have a place for people to work. And then we have a place to work whilst we were doing seismic upgrading, so we provide for an enhanced level of safety along the way.”

In the meantime, legislative staff are working on improving the earthquake response plan, including better securing some of the statues atop the building’s exterior.

Other measures already in effect on the grounds include early warning sensors and accessible containers with emergency supplies.

Staff also hope to have early warning apps installed on mobile phones belonging to legislature employees within the coming months.

Source: http://www.cbc.ca/news/canada/british-columbia/drawings-new-quake-plan-bc-legislature-1.4401890

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Are you ’emergency ready’? The Great B.C. ShakeOut is here

Ahead of Thursday’s Great B.C. ShakeOut — a province-wide earthquake drill — emergency responders are reminding people what it actual means to be “emergency ready.”

“It is not enough for people to purchase a 72-hour emergency kit, to be really ready for any emergency, one needs to have an emergency plan, a kit of supplies, be trained to administer first aid and continue to maintain their supplies and skills for an emergency,” Karen MacPherson, CEO of St. John Ambulance British Columbia and Yukon said in a media release.

A survey of 800 people conducted by Ipsos Reid last April found that just 7 per cent of British Columbians are doing all four things that St. John Ambulance says you need to be ready for a major emergency like an earthquake: create an emergency plan, build an emergency kit, get trained in first aid and fourth, keep all three up to date.

People should be prepared to be sufficient for up to 72 hours.

Despite so few people saying they’re actually doing all four things, the survey — which was commissioned by St. John Ambulance — found that 34 per cent of British Columbians rate their household’s overall level of emergency readiness as “excellent/good.”

St. John Ambulance suggests people check out their website — www.SETforEMERGENCY.com — where they’ve identified “four easy steps to become ’emergency ready,’ complete with a free emergency ready plan and checklist.”

The Great B.C. Shakeout is scheduled for Thursday at 10:19 a.m. At that time, participants should practice how to “drop, Cover and hold on,” St. John Ambulance explained. Register at http://www.shakeoutbc.ca/register.

Source: http://vancouversun.com/news/local-news/are-you-emergency-ready-the-great-b-c-shakeout-is-here

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4.5-magnitude earthquake rattles Vancouver Island

Officials say a small earthquake has struck off the west coast of Vancouver Island.

The United States Geological Survey says the 4.5-magnitude quake struck at 2:26 a.m. Wednesday.

The tremor’s epicentre was recorded about 170 kilometres west of Tofino at a depth of 10 kilometres.

No injuries or damage were reported.

Emergency Info BC said in a tweet that the earthquake did not pose any threat.

Source: http://www.ctvnews.ca/canada/4-5-magnitude-earthquake-rattles-vancouver-island-1.3627640

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Preparing for B.C.’s ‘big one’: What Mexico’s earthquake is telling experts

Preparing for B.C.’s ‘big one’: What Mexico’s earthquake is telling experts

With the death toll of Mexico’s earthquake at 225 and counting and rescue efforts continuing, UBC researchers are weighing in on how a similar quake would affect the Vancouver area.

Carlos Ventura is a professor in civil engineering and the director of the earthquake engineering research facility at UBC. Ventura’s work studies the behaviour of structures under the influence of seismic activity. When asked if the Lower Mainland would see similar destruction to Mexico City, Ventura said not necessarily.

“Mexico City was built on a lake — a dry lake,” he said. “That is like gelatin. Every time there is an earthquake the shaking is always enhanced.”

In Vancouver, the soil conditions are different. Even Richmond, which has softer soil than other areas in the Lower Mainland, doesn’t have the same type of clay that Mexico has.

Even so, Ventura said Mexico’s 7.0 magnitude quake is still a reminder that Vancouver is in “earthquake country.”

“Everybody is always concerned about the ‘big one,’ the subduction earthquake, magnitude nine, etcetera, but the probability of having an earthquake like the one today near Vancouver is very real,” he said. “And that, to us, is the message right now.”

Vancouver resident Jaime Stein is currently in Mexico and felt the earthquake from the 14th floor of an office building. For him, experiencing the shaking first-hand was unlike what he imagined it would be, even though Vancouver’s “big one” is often on his mind.

“I’ve never been in anything like that,” he told CTV News over Skype. “As a Vancouver native you always think about a potential earthquake coming, but when it started moving it was like being on a really rocky boat and your legs aren’t as strong as you think they are. You’re just trying to move as quick as you can and you just hope that it ends quickly.”

Here in Vancouver, Ventura said the quality of construction is a significant factor in how much damage the city would see. Currently, the building code allows buildings to take some damage without collapsing. The philosophy of the building code, he explained, is to ensure people can evacuate safely. Instead, Ventura said some residential homes including mega-homes from the 1980s and quickly constructed mid-rise buildings could be at a greater risk.

“There are some old buildings that have been there for centuries, being subjected to very strong earthquakes and they’re still standing,” he said. “So being old doesn’t mean being bad. It’s just good construction and that makes a difference.”

Source: http://bc.ctvnews.ca/preparing-for-b-c-s-big-one-what-mexico-s-earthquake-is-telling-experts-1.3598789

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‘It was scary really’: Mexicans in B.C. anxious in aftermath of earthquake

Mexicans in B.C. are anxious but determined to help after a 7.1 magnitude earthquake hit Mexico City on Tuesday evening.

According to Mexican officials, 225 people were killed, less than two weeks after an 8.1 magnitude earthquake hit southern Mexico, killing nearly 100 people.

Gustavo Garcia is a cook at a Vancouver restaurant, but his parents and sisters live in Mexico City.

“It was scary really,” he said.

“A lot of buildings — around 30, 40 buildings — went down.

The city was in chaos.

One of the neighbourhoods close to my house was completely destroyed.”

Garcia said he was overcome with relief when his mother called and said his family’s home was safe.

But close by, many people needed help.

“[Across] the street. it was a school. It was a kindergarten and some of the students were trapped in the school as well. A friend of mine called me and said he was trying to help people, that there were people screaming,” said Garcia.

“I wish I could be there to help.”

The quake struck just hours after an annual drill which falls on the anniversary of a deadly earthquake in 1985.

‘It’s like gelatin’

UBC civil engineering professor Carlos Ventura studies earthquakes in an effort to make buildings safer, and has conducted research in Mexico.

He says Mexico City is unique because it is built on the bed of a former lake.

“It is mostly the type of material that is very soft — it’s like gelatin,” he said.

“Imagine a bowl of gelatin that you’re shaking, and in the middle it shakes more and if you put buildings there then the shaking will increase significantly.”

Ventura said he hopes to get a team of Canadian civil engineers together to travel to Mexico City to help in the rescue and rebuilding efforts.

No warning system in B.C.

In many of the videos coming out of Mexico, a droning siren can be heard just before the shaking begins.

Mexico City’s early detection system gave people approximately 10 seconds of warning that the earthquake was coming.

But in B.C., which shares several tectonic similarities with Mexico, there’s still no functional early detection system.

Ocean Networks Canada is developing a detection system for B.C. with $5-million in funding, and plans on delivering the technology to the province in 2019.

Source: http://www.cbc.ca/news/canada/british-columbia/it-was-scary-really-mexicans-in-b-c-anxious-in-aftermath-of-earthquake-1.4298137

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5.1 magnitude earthquake strikes near the Yukon, B.C., Alaska border Saturday

A 5.1 magnitude earthquake struck near the border between Yukon, B.C., and Alaska Saturday afternoon, Earthquakes Canada reports.

The quake happened shortly after 4:30 p.m. PT about 87 kilometres northwest of Skagway, Alaska and 116 kilometres southwest of Whitehorse.

People in Whitehorse reported some shaking Saturday, but there have not been any reports of damage.

Earthquakes Canada — which is part of Natural Resources Canada — says this quake would not be expected to cause significant damages.

In May, a pair of earthquakes struck the region, with a Whitehorse school and office building closing because of the damage in those quakes.

Source: http://www.cbc.ca/news/canada/north/earthquake-yukon-5-1-magnitude-1.4293974

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Minor earthquake strikes west of Port Hardy, B.C.

A 4.7 magnitude earthquake struck 162 kilometres west of Port Hardy, B.C., early Saturday afternoon.

Earthquake Canada said the quake struck at 1:38 p.m. PT and was 10 kilometres deep.

No tsunami advisories have been issued as a result of the quake, and there are no reports so far that anyone felt it.

Source: http://www.cbc.ca/news/canada/british-columbia/minor-earthquake-strikes-west-of-port-hardy-bc-1.4155348

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UBC quake simulation tests retrofits, underscores need to upgrade older buildings

It took about 40 seconds before the effects of the simulated earthquake on the wooden structure were audible: snapping, cracking, popping.

It was the extraordinary sound of nails coming out of the plywood exterior walls of the demonstration, one-room school, and also the sound of the plywood ripping apart between two windows, and the screws pulling away from the drywall.

The wood structure itself, at the height of the two minutes of shaking, swayed side-to-side like a tree in a storm. It was hard to imagine somebody being inside and remaining unhurt.

Modelled after the 9.0 Tohoku temblor in Japan in 2011 that created a devastating tsunami that killed thousands, the test at the University of B.C.’s Earthquake Engineering Research Facility was meant to simulate a large subduction quake off the West Coast, the so-called “Big One,” that would hit Victoria and Vancouver Island, explained Martin Turek, manager of the facility.

Scientists estimate a 10-per-cent probability of the Big One hitting in the next 50 years.

Even on the third test Wednesday on the large shake table, at 120-per-cent beyond what the province’s building code requires, the structure remained largely intact.

However, on inspection after the test, consulting structural engineer Graham Taylor, who has been part of the UBC earthquake research team for nearly 20 years, said such a structure would likely be “red-tagged,” meaning it could no longer be inhabited.

The one-room school had fared well at the 70- and 1oo-per-cent test levels.

That’s good news.

But given that the one-room building, with weights on top to simulate a second floor, was built to demonstrate how a retrofitted school building would perform, it’s also a warning of the damage that would be expected of older buildings that haven’t been upgraded.

Taylor noted that a wooden structure built, for example, in the 1950s would have come apart at one of the two lower-level tests. That’s because they don’t have seismic hold-downs, large bolts that connect the walls to the foundation, and also don’t have the bracket that provides lateral support for walls. The older buildings also aren’t built with half-inch plywood on the outer walls, positioned and nailed optimally to withstand the shaking.

A study released earlier this year, headed by UBC structural engineer Carlos Ventura, director of the university’s quake research centre, found that nearly 4,000 buildings in Victoria are at-risk of complete damage from a major temblor.

Vancouver is at less risk from the Big One off the coast of the Island, because of distance, but is also susceptible to earthquakes on land and in the Strait of Georgia, at shallow and deep levels.

“What we’ve seen here today, we pushed it harder beyond what the code is requiring, and it did very well. So, there’s a huge benefit in upgrading buildings,” said Taylor. “Conversely, when we see this level of damage with a highly engineered structure, and this level of damage would take place with a very low level of shaking for a vulnerable structure, it’s all the more reason we have to think seriously about fixing them (the older buildings) as quickly as possible.”

The tests are also providing information that will help engineers more quickly assess buildings. That’s because the test results, combined with information being collected on soil in specific areas, will pinpoint the most-vulnerable buildings.

That information — showing which buildings are the most vulnerable — will also help underpin the argument for seismically upgrading buildings, said Graham.

The province and municipalities have been slow to act on pro-actively addressing the seismic risk of older buildings. An investigation by Postmedia News, published in 2016, revealed that the City of Vancouver had failed to create a proactive plan to reduce the seismic hazard of the city’s older private buildings despite identifying a need to do so more than two decades ago.

Of more than 1,100 buildings included in a seismic-risk assessment by the city in 1994, hundreds appeared to have had no seismic upgrades, the Postmedia examination also discovered.

Source: http://vancouversun.com/news/local-news/ubc-quake-simulation-tests-retrofits-underscores-need-to-upgrade-older-buildings

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