INDUCED SEISMIC ACTIVITY IN CANADA
SAFETY
WHAT IS INDUCED SEISMICITY?
Seismic activity resulting from human activity is called induced seismicity. It is
associated with several industrial processes, including geothermal energy extraction,
mining, dam building, construction and hydraulic fracturing in oil and natural gas
development.
Seismic activity related to hydraulic fracturing is rarely felt on the surface and
usually occurs near where the rock is being fractured, or 2,000 to 3,000 metres
below ground. The evidence also indicates seismic activity resulting from
hydraulic fracturing has caused no injury or property damage, and poses no
serious risk to workers, public safety or the environment.
Rock is being
fractured 2,000
to 3,000 metres
below ground.
WHAT IS HYDRAULIC FRACTURING?
Hydraulic fracturing is a regulated, safe, and controlled process for recovering oil
and natural gas from tight rock formations such as shale. In Western Canada, the
petroleum industry has used this process for more than 60 years.
Hydraulic fracturing involves the injection of pressurized fluids into the geological
formations where oil and natural gas is locked in dense rock. The pressurized
fluid cracks the rock and creates fissures that extend up to 150 metres from the
horizontal leg of a well, allowing the oil or natural gas to flow into the wellbore to
be collected at surface.
HOW CAN HYDRAULIC FRACTURING CAUSE
SEISMIC ACTIVITY?
The energy released by hydraulic fracturing causes seismic activity. This seismicity
is typically contained underground and rarely felt on the surface. In fact, emerging
scientific consensus suggests hydraulic fracturing poses no serious risk. Seismicity
associated with hydraulic fracturing is usually recorded as microseismic events
not felt on the surface because of their low magnitude. Of the seismic events felt
on the surface, most range from 2.0 ML to 3.0 ML on the Richter scale. This is the
equivalent of vibrations felt by a passing truck on the road. In rare cases, hydraulic
fracturing has caused seismic events of 4.0ML to 4.6ML. Even at these levels,
property damage or risk to public safety is highly unlikely.
CANADASNATURALGAS.CA
SEISMIC ACTIVITY INDUCED BY HYDRAULIC
FRACTURING TYPICALLY TAKES PLACE
WHERE THE SHALE ROCK IS FRACTURED
OR 2,000 TO 3,000 METRES BELOW GROUND.
DEPTH EQUIVALENT TO
ALMOST 4 CN TOWERS
SEPTEMBER 2015
HOW IS INDUCED SEISMICITY REGULATED IN THE OIL
AND NATURAL GAS INDUSTRY?
In British Columbia and parts of Alberta, oil and natural gas companies are
required to monitor for seismic activity associated with hydraulic fracturing on
their operating sites. Companies must also develop, and file with the regulator, a
response plan in the event their operations trigger a seismic event. Any seismic
event over 2.0 ML must be reported to the regulator. In the rare case an event
of magnitude 4.0 ML or greater occurs, hydraulic fracturing operations must
immediately stop allowing for an investigation to be conducted by the regulator.
Operations may only begin again once the regulator has given permission.
SAFETY
QUICK FACTS:
• Minor earthquakes
occur daily across
Canada.
WHAT DOES SCIENTIFIC RESEARCH SAY ABOUT
HYDRAULIC FRACTURING AND SEISMIC ACTIVITY?
ROYAL SOCIETY & ROYAL ACADEMY OF ENGINEERING, JUNE 2012
Shale gas extraction in the UK: A review of hydraulic fracturing
• There is emerging consensus that the magnitude of seismicity induced by
hydraulic fracturing can be felt by few people and the risk of surface impacts,
if any, is negligible.
• On average, more than
4,000 earthquakes
are recorded in Canada
each year, according
to the Geological
Survey of Canada,
of which about 50 are
generally felt.
http://royalsociety.org/uploadedFiles/Royal_Society_Content/policy/projects/shale-gas/2012-06-28
Shalegas.pdf
B.C. OIL AND GAS COMMISSION, AUGUST 2012
Investigation of Induced Seismicity in the Horn River Basin
• “None of the events caused any injury, property damage or posed any risk to
public safety or the environment.”
• Recent earthquakes
in Canada are
tracked by Natural
Resources Canada
and may be viewed
by visiting http://www.
earthquakescanada.nrc
an.gc.ca/recent/index
-eng.php or by
following @CANADA
quakes on Twitter
• More than 8,000 high-volume hydraulic fracturing operations have been
performed in northeastern B.C. with no associated anomalous seismicity.
• Seismic activity related to hydraulic fracturing usually occurs near where the
rock is being fractured.
• Fractures developed during the hydraulic fracturing operations studied for the
report had no effects on shallow aquifers or the environment.
http://www.bcogc.ca/node/8046/download?documentID=1270&type=.pdf
B.C. OIL AND GAS COMMISSION, DECEMBER 2014
Investigation of Observed Seismicity in the Montney Trend
• Improved monitoring in the area recorded 193 seismic events of magnitudes
ranging between 1.0 ML and 4.6 ML in the period from August 1, 2013, to
October 10, 2014 attributed to hydraulic fracturing.
• None of the recorded events resulted in any injuries, property damage or loss
of wellbore integrity.
• The report concludes “a comprehensive regulatory framework is in place ensuring
continued responsible development of unconventional resources in B.C.”
MAGNITUDE IMPACT GLOBAL FREQUENCY
http://www.bcogc.ca/node/12291/download
SEISMIC EVENT FREQUENCY AND IMPACT
9.0
VIBRATIONS FROM PASSING TRUCK
-1 1.0 3.0
-2 0 2.0 4.0
5.0
2011 JAPAN EARTHQUAKE
7.0
6.0
TYPICAL MICROSEISMIC EVENTS DURING HYDRAULIC FRACTURING
8.0
MAGNITUDE (ON RICHTER SCALE)
CANADASNATURALGAS.CA
9 – 9.9
CATASTROPHIC
8 – 8.9
GREAT
1 per decade
1 per year
7 – 7.9
MAJOR
1 per month
6 – 6.9
STRONG
2 per week
5 – 5.9
MODERATE
4 per day
4 – 4.9
LIGHT
1 per hour
3 – 3.9
SMALL
15 per hour
2 – 2.9
MINOR
2 per minute
<2
MICRO
Continual
MICRO: Not felt at surface, causes no damage and can
only be measured deep underground
Source: USGS
SEPTEMBER 2015