Alberni tsunami activity monitored by NEPTUNE sensors

NEPTUNE Canada’s sensor equipment in Barkley Sound detected 10-20 centimetre wave that resulted from the earthquake in Haida Gwaii.

Sensors employed by NEPTUNE Canada picked up a 20 centimetre wave as it rolled up the Alberni Indlet on Saturday night. The wave was generated by the 7.7 magnitude earthquake struck Haida Gwaii that night.

Just because a large tsunami didn’t pour into Port Alberni doesn’t mean there wasn’t tsunami activity in the inlet.

NEPTUNE Canada’s sensor equipment deployed in Folger Passage at the mouth of Barkley Sound detected significant water pressure and seismic activity at 9:47 p.m., ocean dynamic specialist Steve Mihaly said.

Sensor data

“The bottom pressure recorder picked up a 10 to 20 centimetre high wave when it passed through,” Mihaly said.”There was likely some signature of it in Port Alberni but it was after dark and no one may have noticed.”

The signals were triggered by wave activity resulting from a 7.7 magnitude earthquake that struck Haida Gwaii at 8:07 p.m.  The quake was located 139 kilometres south of Masset

The sensors measure bottom pressure and seismic data. In the graphic shown, the top schematic indicates changes in sea level at Folger Passage when the earthquake occurred. The lower plot measured seismic activity that indicates the onset of an earthquake.

A wave isn’t necessarily big when it is out in the deep water. Instead, it is often long to start, then steepens and rises as it slows, he said.

NEPTUNE’s sensors in other area picked up a larger wave when it was further out in the ocean, Mihaly said. “It was going faster offshore because it was in deeper water. But it slowed down and decreased in size as it got nearer to Folger Pass.”

The wave wasn’t a “pure wave” when it arrived, Mihaly said. “By the time it got down here it reflected and bounced around a bit,” he said.

The sensors record changes in the water pressure and detect variances within millimetres.

Sensor data is transmitted to NEPTUNE’s shore station in Port Alberni via fiber optic cable then relayed to the University of Victoria.

Data from Saturday’s activity will be gathered then plugged into a model that will generate scenarios about how a tsunami will interact with the West Coast and what could happen in Port Alberni if it hit, Mihaly said.

Last year, NEPTUNE’s sensors picked up tsunami activity in Port Alberni after an earthquake measuring 8.9 on the Richter scale struck the north east coast of Japan. And they detected water pressure changes after earthquakes in Samoa in 2009 and Chile in 2010.

reporter@albernivalleynews.com

Twitter.com/AlberniNews

Just Posted

Team Harrison prevails in Port Alberni men’s bonspiel

Annual bonspiel drew 20 teams from out of town

Wedding plans derailed following City of Port Alberni’s train announcement

Five wedding parties are scrambling to find alternate transportation arrangements to McLean… Continue reading

Kids help Alberni Aquarium build rockfish luminary for next exhibit

Swimming For Change takes over in time for spring break

Spring fishery closures mulled for south coast

Fewer fish are returning to rivers and more conservation needed, say feds

One dead, two seriously injured in Hwy 4 crash west of Port Alberni

A man has died following a single-vehicle collision west of Port Alberni… Continue reading

VIDEO: Iconic ‘snow cone’ takes shape at B.C. park near Clearwater

Snow cone forming at Wells Gray Provincial Park one that would make Disney’s Queen Elsa proud

UPDATE: Reports of rashes prompt closure of all Harrison Hot Springs pools

Public pool available after Fraser Health shut down all five mineral pools until further notice

Legislation to protect B.C. farmland comes into effect

Regulations enhance food security, encourage long-term farming

Have you heard the legend of Shuswaggi, the Shuswap Lake monster?

Witness accounts as old as 1904, and as recent as 2018, place a creature in the lake’s depths

Credit card fraud steals $50,000 from Victoria businesses: police

Crime Reduction Unit investigating several frauds costing several businesses over $50,000

UPDATE: B.C. ticket holder winner of $25.9-million Lotto Max jackpot

Next draw set for Mar. 1 with an estimated jackpot of $10 million

B.C.-based ‘Team Tardi’ brings home gold in junior curling worlds

In a 9-4 victory over Switzerland, a Langley-based curling team earned its 2nd straight world title

People gather for funeral of seven children killed in fast-moving Halifax fire

Traditional portion of the service will be followed by words from community members

B.C. weavers to help Alaska Native project honouring survivors of violence

Dozens of Chilkat and Ravenstail weavers from all over North America will be weaving 5-inch-by-5-inch squares

Most Read