It would take only 50 minutes to arrive and his advice was that people should not wait if a strong earthquake lasting a minute hit the region. The Kermadec Trench was about as far from Tauranga as Tokyo was from the seat of last year's devastating Japanese earthquake which was felt strongly in Tokyo.
The council has budgeted nearly $380,000 this year and earmarked another $750,000 for civil defence measures to prepare for the big one.
However, the warning won't be delivered by a few big, howling air-raid sirens. Instead there will be dozens of smaller loud-speaker type sirens - enough to blanket all of Mount Maunganui and Papamoa with a minimum 70 decibels of noise.
Mr Somers stressed that the sirens were only part of the answer. The rest was being tackled through the "Tsunami Survive" campaign in which people could participate by clicking on a website or ringing an 0800 number.
Once registered, people were sent a coastal evacuation plan and invited to submit ideas on issues such as where they would go after the sirens went off and how soon they would leave home. The issue boiled down to the size of the tsunami and how far it was away.
Mr Somers expected people to have different ideas about when the sirens should sound if the threat was less immediate, such as eight hours away. The most distant threat was expected to come from an earthquake off the coast of Chile, 16.5 hours' tsunami distance away.
He said the main difference between Tauranga's coastal strip and the inner harbour was that people living along the harbour had a much shorter distance to reach the safety of higher ground in the event of a tsunami.
The location of each siren would determine how many consents would be needed because sirens were allowed in some areas but not in others. Mr Somers said if objections stalled the installation of some, placement of the rest might still go ahead.
People can register for "Tsunami Survive" by going online to www.tauranga.govt.nz/tsunamisurvive or phoning 0800-244-286.
