What is a Marine Threat Tsunami?

What is a Marine Threat Tsunami?
Image: Getty
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On Thursday morning a Marine Threat Tsunami Warning was issued for Lord Howe Island in the Tasman Sea. This is what that means.

Australia’s Bureau of Meteorology (BOM) announced the marine threat Tsunami in the early hours of Thursday morning.

This was the result of a 7.7-magnitude earthquake that hit 417 kilometres east of Tadine in New Caledonia.

“TSUNAMI CONFIRMED. Observation – Norfolk Is at 2:15am AEDT. MARINE THREAT warning for LORD HOWE ISLAND. Issued by JATWC 3:01 AM AEDT Thu 11 Feb 2021. Tsunami affecting marine area commencing after 2:45 am AEDT Thu,” the BOM said on Twitter.

Fortunately, the Tsunami watch was cancelled a few hours later.

“The main tsunami waves have now passed all expected Lord Howe Island locations,” the BOM NSW said on Twitter.

“Small unusual waves may continue, but Tsunami Warnings for Lord Howe Island have been cancelled.”

What is a Marine Threat Tsunami?

In Australia we have an Joint Australian Tsunami Warning Centre (JATWC) ran by the Bureau of Meteorology (BOM) and Geoscience Australia (GA).

It monitors for any Tsunami threats to Australia 24-hours a day.

It has also developed an Australian Tsunami Warning System to determine the level of threat there may be to parts of the country.

“The first stage of the tsunami warning process is a ‘tsunami watch’ phase, where seismologists have determined that there is the potential for an identified undersea earthquake to cause a tsunami threat to Australia,” the BOM website says.

“If there is a threat, the Bureau will issue a National Tsunami Watch.”

In the case of Lord Howe Island, a Marine Threat Tsunami was issued.

According to the BOM, this means that the tsunami has the potential to cause “dangerous rips, strong currents and waves within the marine environment and the possibility of only some localised overflow into the immediate foreshore.”

Comparatively, a Land Threat would mean there is potential for coastal areas to be in danger of “major land inundation, flooding, dangerous rips, waves and strong ocean currents.”