Seismic demonstration not a blast for whales

A not-so-loud blast erupts from Marion Square at noon Tuesday. Activists will do their best to simulate just how deafening a seismic blast would be underwater if oil and natural gas exploration begins offshore.

But they won’t blare air horns to reach the 100-plus decibel threshold they’d like to. The City of Charleston would not permit the demonstration to exceed 65 decibels, the city’s noise limit. A chain saw is about 100 decibels loud; street traffic is about 65 decibels.

The activists plan to blow whistles and clap hand clappers instead, said Katie Parrish, of Oceana, an environmental advocate.

In seismic exploration, loud blasts of compressed air are sounded to gauge echoes for the possible presence of the fuels. Federal regulators are considering giving permits for oil and natural gas exploration offshore to nine companies. Leases are granted for five-year periods. None have been granted in the Atlantic for the next five years.

Conservationists worry that man-made noises could be deafening and frightening and could provoke lethal strandings of sea creatures such as whales, dolphins and sea turtles.