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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

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

‘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

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

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

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

Magnitude 4.2 earthquake detected north of Powell River

A 4.2-magnitude earthquake struck northeast of Powell River, B.C. on Saturday morning.

No damage has been reported and a tsunami is not expected.

The tremor hit 139 kilometres from the Sunshine Coast city around 6:40 a.m., according to Earthquakes Canada.

The agency said the tremor was felt in Port Alberni, Gibsons and other cities in the region.

The USGS rated the magnitude at 4.0, and said it was triggered a little more than 17 kilometres underground.

Source: http://www.cbc.ca/news/canada/british-columbia/magnitude-4-2-earthquake-detected-north-of-powell-river-1.3989825