LAVA FLOW
- a lava flow or simply lava is a product of the quiet
effusion of molten rock or magma from beneath a
volcano.
-When lava flow comes out of a volcanic vent, its
temperature ranges from 700 to 1,200 °C
Lava Effusion and Explosive Eruption
-some molten materias come out to the surface almost unnoticed
while others come out with a bang.
- the amount of gas invloved in eruptions determine not only the
type of material that comes out but also the type of landform a
volcano will be made of.
-the amount of gas invloved is dependent on the viscosity of
magmas, which in turn depends on the composition and
temperature of the magma.
TYPES OF LAVA FLOW:
Basaltic Lava
Andesitic Lava
Rhyolitic Lava
Basaltic Lava
- is the fastest flowing lava because of its relatively low
viscosity.
LAVA FLOW STYLES:
• Pahoehoe
•A's
PAHOEHOE
- is composed of thin flows with smooth surface.
A'S
- have sharp spiny surfaces.
ANDESITIC LAVA FLOW
- are typically associated with strato volcanoes and
commonly from lava domes.
- because of their viscous nature, the surface of andesitic
flow is comprised of smooth-sided fragments.
RHYOLITIC LAVA FLOW
- have relatively higher viscosity that is why these are a
lot slower than andesitic and basaltic flows.
- usually associated with violent eruptions involving
pyroclastic flow.
Other types of Lava:
SHEET LAVA
- are thicker than Pahoehoe amd have surface textures
ranging from ropy to striated.
PILLOW LAVA
- are pillow-shaped rocks formed by the sudden cooling of
lava that is deposited underwater.
Effects of Lava Flow: What makes lava
flow dangerous.
-for its very slow rate of movements, we think of lava as non-life
threatening even if these are extremely hot ( between 550°C and
1,400 °C).
- Deaths attributed to lava flows are often due to related causes,
such as explosive shower of molten spatter over a wide are when
lava interacts with water, explosion of methane gas produced by
lava burial of vegetation, etc.
- Lava flows bring damage or total destruction to land and
properties by burying, crushing or burning everything in their
paths.
Mitigating the effects of Lava Flows
- the best way of course to avoid the effects of lava
flows is to stay away from lava flow danger zone. If
not, the problem is in coming up with ways to stop
the lava flow from heading toward your property or
the community.
Thank You for
listening!