hawaiian tephra

83
Hawaiian Islands Hawaiian Islands Teprha Teprha

Upload: uhhconferencecenter

Post on 14-Jun-2015

200 views

Category:

Technology


0 download

TRANSCRIPT

Page 1: Hawaiian tephra

Hawaiian IslandsHawaiian Islands

TeprhaTeprha

Page 2: Hawaiian tephra

Source for photos and explantions on the web

• http://volcanoes.usgs.gov/Products/Pglossary/pglossary.html

Page 3: Hawaiian tephra

Plinian Eruption Column

Page 4: Hawaiian tephra

• TEPHRA: Any volcanic product ejected into the air.

• Includes pumice, ash, spatter and more!

Page 5: Hawaiian tephra

Volcanic Ash

Page 6: Hawaiian tephra

PUMICE

Page 7: Hawaiian tephra

• Tephra may either be shot into the air ballistically or carried upwards by the convecting column and blown downwind

Page 8: Hawaiian tephra

Eruption Column and Cloud

Page 9: Hawaiian tephra

• Ballistically ejected particles like blocks, bombs, and spatter tend to land near the vent and build cones.

Page 10: Hawaiian tephra

Ballistic Spatter Explosion at Night.

Notice the Parabolic Path of the Spatter.

Page 11: Hawaiian tephra

• Convectively carried material like ash, pele’s hair, light pumice blocks, and reticulite are carried far from the vent by the ash cloud. Deposits from ash clouds get finer away from the vent.

Page 12: Hawaiian tephra

VOLCANIC ASH

Page 13: Hawaiian tephra

Tephra is blown by Winds

Page 14: Hawaiian tephra

• The explosivity of a volcano is related to gas expansion and the viscosity of the magma.

• Abundant gas that expands rapidly provides the force

• Viscosity of magma is the container. If the bubbles escape easily there is little fragmentation. Trapped bubbles explode causing fragmentation.

Page 15: Hawaiian tephra

Explosivity Index

Page 16: Hawaiian tephra

TEPHRA: PYROCLASTIC PRODUCTS

Pyroclastic Products are Called Tephra

Tephra are named first for size, then for texture.

>64 millimeters: Bombs and Blocks (Ballistic)(includes ribbon bombs, teardrop bombs, spatter bombs, pumice bombs–blocks, lava blocks, and lithic blocks)

2 to 64 millimeters: Lapilli(includes pumice, cinder, scoria, reticulite, pele’s tears, pele’s hair, limu o Pele, accretionary lapilli, and lithic lapilli)

<2 millimeters: Ash (includes ash, pele’s hair, limu o Pele,)

Page 17: Hawaiian tephra

• Most of the gas that drives eruptions is water that turns to steam bubbles. The water may either be inside the magma or groundwater mixed into the magma as it rises to the surface.

Page 18: Hawaiian tephra

Hawaiian style eruptions

• Generally fairly gentle as the magma is very fluid and allows the bubbles to pass through without causing violent explosions.

Page 19: Hawaiian tephra

Hawaiian Fire Fountain

Page 20: Hawaiian tephra

Reticulite

Page 21: Hawaiian tephra

Reticulite––lapilli

Page 22: Hawaiian tephra

Reticulite Bomb

Page 23: Hawaiian tephra

Pele’s Hair

Page 24: Hawaiian tephra

Cinders

Page 25: Hawaiian tephra

Cinder lapilli at Pu‘u Puai

Page 26: Hawaiian tephra

Pele’s Tears––Lava droplets

Page 27: Hawaiian tephra

Low Fountain and Tephra Cone––Pu‘u ‘Ō‘ō

Page 28: Hawaiian tephra

Dome Fountain

Page 29: Hawaiian tephra
Page 30: Hawaiian tephra

Spatter Bombs in Flight

Page 31: Hawaiian tephra

Spatter Deposits

Page 32: Hawaiian tephra
Page 33: Hawaiian tephra

Pele’s Hair From Skylight

Page 34: Hawaiian tephra

Strombolian style eruptions

These eruptions are marked by bursts of gas that are more explosive than Hawaiian eruptions due to the greater viscosity of the magmas that keeps gas from escaping easily.

Builds cinder cones like those seen on Mauna Kea, Hualālai, Haleakala, etc.

Page 35: Hawaiian tephra
Page 36: Hawaiian tephra
Page 37: Hawaiian tephra
Page 38: Hawaiian tephra
Page 39: Hawaiian tephra

Cinder Cone

Kohala Mountains

Cinders and Bombs

Page 40: Hawaiian tephra

Volcanic Bomb––Mauna Kea

Page 41: Hawaiian tephra

Small Volcanic Bombs––really lapilli!!

Page 42: Hawaiian tephra

Pumice Bomb at Pu‘u Waa Waa

Page 43: Hawaiian tephra

• Explosive Hawaiian eruptions that make ash are all driven by groundwater or seawater mixing with the magma.

Page 44: Hawaiian tephra

Ballistic Spatter at Ocean Entry

Page 45: Hawaiian tephra
Page 46: Hawaiian tephra

Large Lithc Block in Spatter Field at Ocean Entry––

Related to Collapse of Bench and Large

Steam Explosion

Page 47: Hawaiian tephra

Spatter and Steam Cloud

Page 48: Hawaiian tephra

Ballistic Spatter and Steam Cloud

Page 49: Hawaiian tephra

Limu o Pele bubble bursting

Page 50: Hawaiian tephra

Limu o Pele

Page 51: Hawaiian tephra

Limu O Pele

Page 52: Hawaiian tephra

Coarse Littoral Ash from Steam Plume

Page 53: Hawaiian tephra
Page 54: Hawaiian tephra

Footprints in Ash

Page 55: Hawaiian tephra
Page 56: Hawaiian tephra
Page 57: Hawaiian tephra

Accretionary Lapilli

Page 58: Hawaiian tephra

Accretionary Lapilli in Keanakako`i Ash near Footprints

Page 59: Hawaiian tephra

Diamond Head is made of ash and accretionary lapilli.

Page 60: Hawaiian tephra

Koko Head

Page 61: Hawaiian tephra
Page 62: Hawaiian tephra
Page 63: Hawaiian tephra
Page 64: Hawaiian tephra
Page 65: Hawaiian tephra
Page 66: Hawaiian tephra
Page 67: Hawaiian tephra
Page 68: Hawaiian tephra
Page 69: Hawaiian tephra
Page 70: Hawaiian tephra
Page 71: Hawaiian tephra
Page 72: Hawaiian tephra
Page 73: Hawaiian tephra
Page 74: Hawaiian tephra
Page 75: Hawaiian tephra
Page 76: Hawaiian tephra
Page 77: Hawaiian tephra
Page 78: Hawaiian tephra
Page 79: Hawaiian tephra

Pumice

Page 80: Hawaiian tephra

Volcanic Ash––Electron Microscope Photo

Page 81: Hawaiian tephra
Page 82: Hawaiian tephra
Page 83: Hawaiian tephra