Seismologists say the ShakeAlert system didn’t work properly ahead of Thursday’s 6.0 magnitude earthquake near the California-Nevada border, but they do know why. Ian Cull reports. Stay connected: Follow us on Twitter: http://www.twitter.com/nbcbayarea Like us on Facebook: http://www.facebook.com/nbcbayarea Follow us on Instagram: http://www.instagram.com/nbcbayarea Add us on Snapchat @NBCBayArea Catch up on all the day's news: http://www.nbcbayarea.com Download our app: On iOS: http://nbcbay.com/R1BhqYM On Android: http://nbcbay.com/rUcA97h