lines and the fact that most of Quebec sits on a large rock shield prevented current flowing through the earth, finding a less resistant path along the 735 kV power lines. The James Bay network went offline in less than 90 seconds, giving Quebec its second massive blackout in 11 months. The power failure lasted 9 hours and forced the company to implement various mitigation strategies, including raising the trip level, installing series compensation on ultra high voltage lines and upgrading various monitoring and operational procedures. Other utilities in North America, the UK, Northern Europe and elsewhere implemented programs to reduce the risks associated with geomagnetically induced currents. Since 1995, geomagnetic storms and solar flares have been monitored from the Solar and Heliospheric Observatory (SOHO) joint-NASA-European Space Agency satellite. August 1989 geomagnetic storm In August 1989, another geomagnetic storm affected microchips, leading to a halt of all trading on Toronto's stock market. This geomagnetic storm was caused by a very large X20 solar flare on August 16, 1989, which was even stronger than the X15 flare from March 6, 1989, referred above. Sunquakes discovered "Sunquakes" caused by solar flares were first observed during this cycle. These are running acoustic waves, as opposed to the standing waves that constitute the material of helioseismology. The flare impulse launches these waves from the photosphere, and they arc deeply into the interior of the Sun before refracting back to the surface to appear as faint ripples, expanding radially away from the flare some tens of minutes later. The flare in which these waves were first observed, SOL1996-07-09, occurred more than three years after the last previous major event. See also Solar variation List of solar cycles References Solar cycles