KRAKATOAKRAKATOAHydro-Hydro-

Volcanic VolcanicExplosionExplosion

andandTsunamiTsunami

KrakatoaKrakatoa

Krakatoa exploded August 27, 1883 Krakatoa exploded August 27, 1883 obliterated 5 square miles leaving a obliterated 5 square miles leaving a crater 3.5 miles across and 200-300 crater 3.5 miles across and 200-300 meters deep.meters deep.

33 ft high tsunami waves hit Anjer 33 ft high tsunami waves hit Anjer and Merak demolishing the towns and Merak demolishing the towns and killing most of the people and killing most of the people

> 10,000. In Merak wave rose to 135 > 10,000. In Merak wave rose to 135 ft ASL and moved 100 ton Coral ft ASL and moved 100 ton Coral blocks up on the shore.blocks up on the shore.

Krakatoa TsunamiKrakatoa Tsunami

Tsunami swept over 300 coastal Tsunami swept over 300 coastal towns and villages. Over 40,000 towns and villages. Over 40,000 were killed by the tsunami waves.were killed by the tsunami waves.

Sea withdrew at Bombay, India and Sea withdrew at Bombay, India and killed one person in Sri Lanka.killed one person in Sri Lanka.

Tsunami produced by explosion and Tsunami produced by explosion and associated shock wave and associated shock wave and pyroclastic flows.pyroclastic flows.

Krakatoa Before and After Krakatoa Before and After ExplosionExplosion

New Volcano – Anak Krakatau - New Volcano – Anak Krakatau - 19831983

Travel Time of Major Tsunami from Travel Time of Major Tsunami from 44thth Explosion and Collapse Explosion and Collapse

Area FloodedArea Flooded

Max Run-up Heights (meters)Max Run-up Heights (meters)

Jakarta Tide Jakarta Tide

GaugeGauge

BarographBarographRecordRecord

shows early shows early arrival of arrival of the atmos the atmos pressure pressure

waveswaves

Tide Gauge Records from Tide Gauge Records from Atmospheric Pressure WavesAtmospheric Pressure Waves

HYDROVOLCANIC EXPLOSIONSHYDROVOLCANIC EXPLOSIONS

Generated by Interaction of Magma Generated by Interaction of Magma with ground water.with ground water.

Called Surtseyan after 1963 eruption Called Surtseyan after 1963 eruption off Iceland.off Iceland.

Water flashes to steam and expands Water flashes to steam and expands explosivelyexplosively

HH22OO(LIQUID) (LIQUID) > > HH22OO(GAS) (GAS) at constant at constant volume has volume has a 30 Kbar PRESSUREa 30 Kbar PRESSURE

Modeling Hydrovolcanic ExplosionsModeling Hydrovolcanic Explosions

Water described as an Explosive and a Water described as an Explosive and a propagating detonation is modeled for propagating detonation is modeled for hot liquid water going to gas.hot liquid water going to gas.

BKW steady state conditions of C-J state BKW steady state conditions of C-J state of 89 kbar, 5900 m/sec, 0.75 cc/gm, of 89 kbar, 5900 m/sec, 0.75 cc/gm, 11001100o o K for liquid water with -46.3 K for liquid water with -46.3 kcal/mole Heat of Formation to model kcal/mole Heat of Formation to model energy (19 kcal/mole) for hot lava energy (19 kcal/mole) for hot lava heating water to ~1100heating water to ~1100o o K.K.

Krakatoa ModelKrakatoa ModelSpherical GeometrySpherical Geometry

100 m Water

3 4 10 Km500 m Hot Spot

2

0

Km

-3

200 m

BASALT

AXIS

Hydrovolcanic ExplosionHydrovolcanic Explosion

0.1 sec

0.2 sec 0.3 sec

KRAKATOA HYDROVOLCANIC ERUPTION – Density ContoursKRAKATOA HYDROVOLCANIC ERUPTION – Density Contours

0.4 Sec 0.5 Sec

0.6 Sec 0.7 Sec

0.4 Sec 0.5 Sec

0.6 Sec0.7 Sec

Krakatoa Hydrovolcanic EruptionKrakatoa Hydrovolcanic EruptionDensity ContoursDensity Contours

1.0 Sec 1.5 Sec 2.0 Sec

3.2 Sec 10.0 sec

Krakatoa Hydrovolcanic EruptionKrakatoa Hydrovolcanic EruptionX-velocity contoursX-velocity contours

Note Strong Air shock

0.4 Sec 1 Sec

2 Sec

10 Sec

Krakatoa Hydrovolcanic EruptionKrakatoa Hydrovolcanic EruptionDensity ContoursDensity Contours

First

0.67

sec

MOVIES AVAILABLE on NMWW DVD

4 km 5 km 4 km 5 km

8 kmWAVE

Profile

TSUNAMI WAVETSUNAMI WAVERadius Wave Height PeriodRadius Wave Height Period

4 km 130 meters 25 sec4 km 130 meters 25 sec

5 km 48 meters 12 sec5 km 48 meters 12 sec

8 km 7.5 meters 6 sec8 km 7.5 meters 6 sec

Inside the hydrovolcanic explosion at Inside the hydrovolcanic explosion at

1.5 km radius it expands up for more 1.5 km radius it expands up for more

than 2 km with initial pressure >25 kbthan 2 km with initial pressure >25 kb

Did it look like 1946 Bikini Shot?Did it look like 1946 Bikini Shot?

21 Kt at 27 m depth – Krakatoa 150-200 megatons

KrakatoaKrakatoa

The tsunamis had periods of less The tsunamis had periods of less than 5 minutes and wavelength of than 5 minutes and wavelength of less than 7 km thus rapidly decayed.less than 7 km thus rapidly decayed.

The far field effects were negligible The far field effects were negligible but recorded on tide gauges around but recorded on tide gauges around the world. Caused by air shock the world. Caused by air shock propagating and coupling to the propagating and coupling to the ocean.ocean.