JMdict entry #1719720

1. noun (common) (futsuumeishi)noun or participle which takes the aux. verb suruintransitive verb horizontal shaking (of an earthquake)
   see: 縦揺れ・1
2. noun (common) (futsuumeishi)noun or participle which takes the aux. verb suruintransitive verb rolling (of a boat, aircraft, etc.); swaying