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Maar

A maar is a broad, low-relief volcanic crater that forms from a phreatomagmatic eruption caused by the interaction of groundwater with magma. The explosive steam-driven activity ejects ash, tephra, and blocks, leaving a wide, circular depression at the surface.

Formation and morphology: The eruption occurs when rising magma heats groundwater, producing rapid steam expansion that

Distribution and significance: Maars occur in volcanic fields where groundwater is present and magma is near

Notable examples: Meerfelder Maar and Pulvermaar in Germany are among the best-described maars. Worldwide, maars vary

Ecology and current use: Crater lakes hosted by maars often support diverse ecosystems and are popular sites

fragments
rock
and
excavates
a
crater.
The
resulting
vent
commonly
develops
a
ring
of
ejecta
and
a
surrounding
tuff
ring;
a
deeper
vent
may
create
a
diatreme
beneath
the
crater.
After
activity
ceases,
the
crater
may
fill
with
water
to
form
a
maar
lake
or
remain
dry.
the
surface.
They
are
common
in
continental
rift
zones
and
intraplate
volcanic
regions,
with
well-studied
examples
in
the
Eifel
region
of
Germany
and
other
parts
of
Europe,
as
well
as
in
other
continents.
in
size
from
tens
to
hundreds
of
meters
across.
for
recreation
and
tourism.
Maars
also
provide
records
of
past
eruption
and
hydrological
conditions.