text: The second Storegga event resulted in one of these phenomena.
full_question: The second Storegga event resulted in one of these phenomena. These phenomena can create symmetricalexamples of parabolic dunes that contain angular clasts or mud in addition to sand and are named chevronsfor their inverted-v shape. An intensity scale for these phenomena was devised by Soloviev. The PTWC wasfounded after one of these phenomena devastated Hilo. Their deposits are difficult to distinguish from thoseleft by hurricanes because both deposit continuous and discontinuous sand sediments, sometimes withisolated boulders, across large areas of coast. These natural hazards are shallow water waves even in the deepocean due to their long wavelength. For 10 points, name these fast moving waves, created by submarinelandslides and earthquakes, that can devastate coasts. 
first_sentence: The second Storegga event resulted in one of these phenomena.
raw_answer: tsunamis [or seismic sea waves; prompt on harbor waves or earthquakes] 