NIWA scientists are heading to the waters around
Whakaari/White Island in the Bay of Plenty next week to
survey changes to the seafloor.
Mapped in 2005 and
again in 2019, the area is known for its underwater vents
and canyons. However, the eruption of Whakaari/White Island
in December last year is likely to have significantly
altered the seafloor landscape.
NIWA marine geologist
Dr Joshu Mountjoy says the survey work will help
understanding of how much sediment was dislodged in the
eruption and where it has gone.
“What is visible
from sea level is only a small part of the volcano – most
of it is under the ocean so we want to see how that
submarine environment has changed.”
Scientists will
be on board NIWA research vessel Tangaroa and will map the
area using a multibeam echo sounder which emits sound beams
that map the seafloor and objects in the water column such
as gas bubbles. This technology does not disturb the
seabed.
Water samples will also be taken to measure
methane and carbon dioxide gas levels which will help detect
the presence of underwater seeps linked to volcanic
activity.
Dr Mountjoy says the aim of the survey is to
understand how these sedimentary deposits have changed and
if there have been any submarine landslides.
“There
is also the potential to see new hydrothermal vents –
particularly in shallow water close to the island. No-one
has collected water column imaging close to Whakaari so this
is an incredible opportunity to discover new areas of
volcanic activity.”
The scientists will also be
looking for significant changes that may have affected the
ecology of the area that may require further work.
The
survey is part of a nine-day voyage led by fisheries
acoustics scientist Dr Yoann Ladroit starting on July 22
that will also survey the chemical composition of gases
released by the hydrothermal vents on what is known as the
Calypso vent field in the Bay of Plenty.
Results will
be made public over the next few
months.
