. . "magnitude 6.6 earthquake with its epicentre under Lake Grassmere" . . "6.6 magnitude" . "4" . . . "Lake Grassmere earthquake" . . . "magnitude 6.6 earthquake" . "A 6.6 M_W earthquake" . . . . . "2013 Lake Grassmere earthquake" . "6.6" . "second earthquake" . . "2013 Lake Grassmere earthquake" .