In addition to the liquefaction observations, lake-ice cracking supported directivity affects on ground motion. Many lakes dot the region and these lakes were for the most part frozen during the time of the earthquake. Cracking of the surface ice due to ground shaking was prevalent over the entire region. Cracked lake ice was observed within 30 to 40 km out from the fault along the western portion of the rupture, whereas, the affected region was much larger toward the east where lake ice cracking extended out to approximately 100 km from the fault.