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  • Rare Magnitude-5.0 earthquake reported in Canada

    <CITE class=vcard>Magnitude-5.0 earthquake reported in Canada

    </CITE>
    <CITE class=vcard></CITE>
    <CITE class=vcard></CITE>
    <CITE class=vcard>By CHARMAINE NORONHA, Associated Press Writer Charmaine Noronha, Associated Press Writer </CITE>? <ABBR class=recenttimedate title=2010-06-23T12:38:19-0700>16 mins ago</ABBR>
    <!-- end .byline --> <CITE class=caption>AFP/File ? A quake reading on a seismograph. A strong earthquake shook Ottawa and Montreal in eastern Canada on ? </CITE>


    TORONTO ? A magnitude-5.0 earthquake struck at the Ontario-Quebec border region of Canada on Wednesday, the U.S. Geological said, shaking homes and businesses from Canada's capital in Ottawa on south to Cleveland and Cincinnati in Ohio.

    There were no immediate reports of injuries or damage.

    The midday quake was felt in Canada and in a number of U.S. states, including Michigan, Ohio, Pennsylvania, Vermont, New Jersey and New York.

    The USGS said the quake occurred at a depth of about 12 miles (19.2 kilometers). The agency initially said the quake had a 5.5 magnitude, but later reduced it to a magnitude-5.0. The quake occurred at 1:41 p.m. EDT (1741 GMT), the USGS said.

    The quake came just ahead of the weekend summit of G-20 and G-8 world leaders in Toronto and Huntsville, Ontario.

    The tremors, which lasted about 30 seconds, rattled buildings in Ottawa and Toronto, as well as government offices across the Ottawa River in Gatineau, Quebec.

    Several buildings in Toronto and the Ottawa region were evacuated.
    Chris Cornell, 46, who works in downtown Toronto, said desks and furniture shook as he sat at his desk in a finance office.
    Shirley Pelletier, 27, said a prolonged tremor shook bookshelves and caused paintings on walls to shake in her office just outside downtown Toronto.

    Residents of a number of states in the Midwest and Northeast reported feeling the earthquake.

    In Ohio, people reported the sound of plaster cracking in Cleveland and buildings in Cincinnati gently swaying.

    In Cleveland, James Haselden says his office in a renovated 19th century brick building swayed and he heard plastic cracking but saw no damage.

    The Pittsburgh Post-Gazette reported on its website that the Canadian quake was felt by some residents in the western Pennsylvania area.

    The quake also was felt in New Jersey, where the Bergen County administration building in Hackensack was evacuated after employees reported they felt a tremor.

    Bergen County Police Lt. Christine Francois said numerous people in the Hackensack and Englewood areas called police to report earth tremors.

    In Michigan, residents from suburban Detroit to Port Huron and Saginaw reported feeling the earthquake.

    Detroit police spokeswoman Yvette Walker told The Associated Press that police personnel on the upper floors of the downtown headquarters building reported feeling the quake.


    In New York state, people from Buffalo to Albany and north to Massena on the St. Lawrence River said pets were startled and plates rattled when the quake hit.

    .../

    "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
    -Nelson Mandela

  • #2
    Re: Rare Magnitude-5.0 earthquake reported in Canada

    Magnitude 5.0 - ONTARIO-QUEBEC BORDER REGION, CANADA

    2010 June 23 17:41:42 UTC


    Earthquake Details


    <TABLE id=parameters summary="Earthquake Details" sizset="24" sizcache="3"><TBODY sizset="24" sizcache="3"><TR sizset="22" sizcache="2"><TH sizset="22" sizcache="2">Magnitude</TH><TD>5.0</TD></TR><TR sizset="24" sizcache="3"><TH sizset="23" sizcache="2">Date-Time</TH><TD sizset="24" sizcache="3"></TD></TR><TR sizset="25" sizcache="2"><TH sizset="25" sizcache="2">Location</TH><TD>45.862?N, 75.457?W</TD></TR><TR sizset="26" sizcache="2"><TH sizset="26" sizcache="2">Depth</TH><TD>18 km (11.2 miles) set by location program</TD></TR><TR sizset="27" sizcache="2"><TH sizset="27" sizcache="2">Region</TH><TD>ONTARIO-QUEBEC BORDER REGION, CANADA</TD></TR><TR sizset="28" sizcache="2"><TH sizset="28" sizcache="2">Distances</TH><TD>
    • 38 km (24 miles) N (356?) from Cumberland, Ontario, Canada
    • 44 km (28 miles) NNE (21?) from Gatineau, Qu�bec, Canada
    • 51 km (32 miles) NNE (26?) from Hull, Qu�bec, Canada
    • 53 km (33 miles) NNE (21?) from OTTAWA, Ontario, Canada
    </TD></TR><TR sizset="29" sizcache="2"><TH sizset="29" sizcache="2">Location Uncertainty</TH><TD>horizontal +/- 2.3 km (1.4 miles); depth fixed by location program</TD></TR><TR sizset="30" sizcache="2"><TH sizset="30" sizcache="2">Parameters</TH><TD>NST=283, Nph=283, Dmin=148.6 km, Rmss=0.91 sec, Gp= 25?,
    M-type=teleseismic moment magnitude (Mw), Version=8
    </TD></TR><TR sizset="31" sizcache="2"><TH sizset="31" sizcache="2">Source</TH><TD>
    • USGS NEIC (WDCS-D)
    </TD></TR><TR sizset="32" sizcache="2"><TH sizset="32" sizcache="2">Event ID</TH><TD>us2010xwa7</TD></TR></TBODY></TABLE>
    • This event has been reviewed by a seismologist.
    http://earthquake.usgs.gov/earthquak...us2010xwa7.php
    "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
    -Nelson Mandela

    Comment


    • #3
      Re: Rare Magnitude-5.0 earthquake reported in Canada

      Earthquake Summary


      Tectonic Summary


      The June 23, 2010 Ontario-Quebec border region earthquake occurred at 1:42 pm local (eastern) time about 60 km (38 miles) north of Ottawa, Ontario, Canada's capital city. The preliminary estimate of magnitude (M) is 5.0, at a depth of roughly 19 km (12 miles). These estimates may change as more data becomes available.

      This earthquake occurred near the southern edge of the Western Quebec Seismic Zone. Earthquakes within this zone are mostly small. They tend to cluster in a wide area that is slightly elongated northwest-southeast. Historically, earthquakes in the Western Quebec Seismic Zone have caused damage roughly once a decade. Three or four smaller events each year are felt in the region but are generally too small to cause damage. The largest earthquakes known in this part of Canada occurred in 1935 (M6.1), about 250 km (150 miles) to the northwest of todays event, and in 1732 (M6.2), about 150 km (100 miles) to the east. The 1732 earthquake caused significant damage in Montreal.

      Earthquakes of the size of todays event are uncommon east of the Rockies, but many have occurred since the arrival of European settlers three centuries ago. In eastern North America and geologically similar regions worldwide, M5.0 to M5.5 earthquakes typically cause light to moderate damage out to a few tens of kilometers (miles) from the epicenter, depending on the number of people and type of buildings near the epicenter. Typically these earthquakes are felt hundreds of kilometers (miles) away. Earthquakes of this size and depth are unlikely to rupture the Earth's surface, although exceptions are known.

      The main faults near this earthquake zone trend northwest. These faults form the Ottawa graben and were most active several hundred million years ago. Some of the faults of the graben have been reactivated one or more times since then. The initial focal mechanism of todays earthquake suggests reverse faulting on a fault trending southeast-northwest. However, the size and depth of this earthquake make it uncertain whether the causative fault can be identified.

      EARTHQUAKES IN THE WESTERN QUEBEC SEISMIC ZONE

      People in the large Western Quebec seismic zone have felt small earthquakes and suffered damage from larger ones for three centuries. The two largest damaging earthquakes occurred in 1935 (magnitude 6.1) at the northwestern end of the seismic zone, and in 1732 (magnitude 6.2) 450 km (280 mi) away at the southeastern end of the zone where it caused significant damage in Montreal. Earthquakes cause damage in the zone about once a decade. Smaller earthquakes are felt three or four times a year.

      Earthquakes east of the Rocky Mountains, although less frequent than in the west, are typically felt over a much broader region. East of the Rockies, an earthquake can be felt over an area as much as ten times larger than a similar magnitude earthquake on the west coast. A magnitude 4.0 eastern earthquake typically can be felt at many places as far as 100 km (60 mi) from where it occurred, and it infrequently causes damage near its source. A magnitude 5.5 eastern earthquake usually can be felt as far as 500 km (300 mi) from where it occurred, and sometimes causes damage as far away as 40 km (25 mi).

      FAULTS

      Earthquakes everywhere occur on faults within bedrock, usually miles deep. Most of the bedrock in the Western Quebec seismic zone was formed as several generations of mountains rose and were eroded down again over the last billion or so years.

      At well-studied plate boundaries like the San Andreas fault system in California, often scientists can determine the name of the specific fault that is responsible for an earthquake. In contrast, east of the Rocky Mountains this is rarely the case. The Western Quebec seismic zone is far from the nearest plate boundaries, which are in the center of the Atlantic Ocean and in the Caribbean Sea. The seismic zone is laced with known faults but numerous smaller or deeply buried faults remain undetected.
      Even the known faults are poorly located at earthquake depths.

      Accordingly, few, if any, earthquakes in the seismic zone can be linked to named faults. It is difficult to determine if a known fault is still active and could slip and cause an earthquake. As in most other areas east of the Rockies, the best guide to earthquake hazards in the Western Quebec seismic zone is the earthquakes themselves.
      <!--Western Quebec.doc, 07/23/03, Page 1 of 1-->


      Earthquake Information for Canada

      "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
      -Nelson Mandela

      Comment


      • #4
        Re: Rare Magnitude-5.0 earthquake reported in Canada

        Earthquake survey maps that shaking feeling

        Last Updated: Tuesday, June 29, 2010 | 3:26 PM ET

        CBC News


        An earthquake hit at 1:41 p.m. ET on June 23 south of Echo Lake, Que., 60 kilometres north of Ottawa, near the Ontario border, and was felt across southern and eastern Ontario and western Quebec. (CBC)

        Ontario and Quebec residents shaken by the magnitude 5.0 earthquake last week are being asked to share their experiences with a federal research project.

        The epicentre of the June 23 earthquake was about 50 kilometres north of Ottawa, and it was felt across southern and eastern Ontario and western Quebec, as well as in some U.S. states, including Michigan, Ohio, Pennsylvania, Vermont, New Jersey and New York.

        Greg Brooks, a research scientist with the Geological Survey of Canada at the Department of Natural Resources in Ottawa, said it's rare for an earthquake of that magnitude to happen in a highly populated area, so scientists are taking advantage of that.

        "This is a fantastic opportunity to get feedback from the public ? so we can look at the patterns of shaking throughout the Ottawa area," he said.

        He is encouraging people in the Ottawa area and beyond to fill out a questionnaire on the department's Earthquakes Canada website about where they were and how they felt during the earthquake. Questions ask how long the shaking lasted, whether objects fell off shelves and what type of damage there was to the building they were in.

        "This helps us better understand how the geology of the area reacts to seismic shaking," he added.

        Soft soils shakier

        The type of soil or rock underfoot can make a huge difference in the way an earthquake feels, Brooks explained.

        "In general, we would expect there to be more seismic shaking on the areas of thick, soft sediment ? thick leda clay ? than there would be on areas where there's bedrock on the earth's surface."

        In fact, the national building code takes that into account, requiring more earthquake resistance in buildings built on clay than those on bedrock.

        Not only are there many areas of thick clay in the Ottawa area ? such as Orl?ans ? but there are lots of abrupt local changes in geology in the region separated by just a couple hundred metres, Brooks said.

        That geology has already been mapped, but researchers don't yet know how closely that corresponds to the way the shaking actually feels.

        Researchers hope to be able to superimpose the results of the questionnaire on the geological map of the region, Brooks added ? "to see if we are seeing the patterns that we would expect to see based on the geology of the Ottawa area."

        As of Tuesday afternoon, the results of 1,107 surveys had been mapped.
        As of Tuesday afternoon, 1,107 survey results had been mapped. (Earthquakes Canada)


        Read more: http://www.cbc.ca/canada/ottawa/stor...#ixzz0sHcWhIMc
        "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
        -Nelson Mandela

        Comment

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