ocr: Ar rapidly expanding sun quake' as recorded by MDI. The seismic wave, which was caused by a moder- ately-sized solar flare on 6 July 1996, spread ouf more than 100,000 km on the solar surface, looking much like ripples spreading from a rock dropped into a pool of water. The solar waves accelerated from an initial speed of 35,000 km/h to a maximum of 400,000 km/h before disappearing.
