Access Data
Tsunami deposit and proxy data are available through the NCEI Hazardous Event Lookup (HaZEL) search tool.
Tsunami Deposits
Tsunami deposits are the physical evidence a tsunami has impacted a shoreline or submarine sediments. These deposits can be preserved in the geologic record and studied long after the tsunami waves dissipate. Tsunami researchers use various criteria to determine whether a tsunami generated a deposit. Distinguishing tsunami deposits from storm deposits generates vigorous debate among scientists. Storm deposits often contain fine laminations that are rarely seen in tsunami deposits.
In some cases, the absence of a deposit provides critical information regarding the magnitude of a tsunami. A series of dunes may block the water from a tsunami, preserving the area behind the dunes, while complete destruction is observed where there was no barrier to the tsunami's impact. The height of the dunes limits the estimate of tsunami water height.Criteria commonly used to identify tsunami deposits include:
- sharp, erosive contact with underlying material
- one or more layer(s) of material that fine upward (grain size gets smaller toward the top of the layer)
- layers that thin landward
Tsunami Proxies
Tsunami proxies are evidence that indicate an event capable of producing a tsunami occurred, but do not contain direct evidence of a tsunami. Proxies include coseismic subsidence, turbidite deposits, changes in biota following an influx of marine water in a freshwater environment, etc. These data complement the tsunami deposits data by allowing calculation of recurrence intervals of events capable of producing tsunamis.