Heartbeat of a volcano

3 days ago these lava flows erupted in fiery fountains materials thrown up from the Earth's interior have transformed this land now Rising water vapor and hot gases are the only signs of activity at the volcano's vent while the lava is still hot beneath its crust scientist arrive to investigate the effects of the eruption we will join them portable seismometers and a recording seismograph are set up to monitor the volcano the czer graph shows that activity continues below the surface National Bureau of Standards wwvh Maui Hawaii next tone begins at 21 hours 15 minutes Greenwich meantime [Music] some equipment has been destroyed by the lava flow long sections of cable must be replaced cable is laid across the new lava Beyond which a seismometer is positioned by cable signals from the seismometer are transmitted to the Hawaiian volcano Observatory staffed by scientist of the United States Geological Survey B Del base Del over what do you see in the pit what do you see in the pit over right now here movements of the active volcano are continuously recorded a clue to the dynamic forces within the Earth on the island of Hawaii are two of the world's largest volcanoes Mona and monoa east of monoa is kilaa one of the Earth's most studied active volcanoes the activity we are investigating is on the East Rift zone of kilaa 15 km away is kila's Summit at the summit overlooking the Caldera is the volcano Observatory from The Observatory cables go out to size MERS strategically placed around the mountain sensor signals are transmitted to the observatory where a bank of seismographs continuously records them here we see the tracing during a relatively quiet period the needle crosses a previously recorded earthquake suddenly a new earthquake occurs indicating movement of the volcano most of these earthquakes can only be detected by sensitive seismometers they cannot be felt by man tracings for a 24-hour period reveal frequent earthquakes as many as 50 to 100 a day of differing magnitudes the shaking of an earthquake lasts only a short time but harmonic Tremor may go on for days harmonic Tremor is probably caused by the movement of magma within the volcano movement of magma may also cause changes in the shape of the volcano changes in the tilt of the mountain slopes are measured with a sensitive leveling instrument set up at the center of a triangle the corners of the triangle are marked by calibrated rods a change in the tilt of the land will move the rods up or down in relation to one another these changes are detected by the leveling instrument a tent protects the instrument from the influences of direct sunlight and wind tilt triangles are set up at many locations on the volcano in weather of all kinds repeated measurements of the Tilt are made at each triangle from these measurements calculations are made to show changes in the volcano shape the results plotted on a graph show that during the last eruption the volcano deflated rapidly but that since then it has started to inflate once more as the swelling continues hot gases are observed at the vent this degassing provides a rare opportunity to gather samples of gases from within the volcano gases pass through metal tubing into a collecting jar the vent is closely watched degassing accompanied by lava spatter May suddenly increase [Music] as swelling continues the summit Caldera expands to measure the expansion a gometer is positioned over a permanent marker on one side of the Caldera a beam of light is directed at a reflector on the opposite side of the Caldera 5 km away by measuring the travel time of light the geometer detects changes in this distance as small as a few millimet calculations show that the geodimeter stations on the summit have moved apart several centimet since the last eruption further evidence that the volcano is inflating a few days later observers at the vent report lava is rising the mounting activity is immediately reported to the observatory By Radio direct observations are as important as the data supplied by instruments as pressure continues to build within the volcano lava overflows the vent 15 minutes later the lava flows back into the vent ending a short eruptive cycle though small in scale this activity provides many of the features of a major eruption and a hint of what is to come later the portable seism graphs show increasing harmonic Tremor at some locations the needle swings wide at others the tracing Narrows data from several stations are plotted on a map and compared the data show that the greatest activity is closest to station number one near the vent continuing measurements suggest that molten rock is moving overnight lava forms a spatter cone at the vent observers keep a close watch on the activity lava gushes from the vent flows only a few meters and pours back into the [Music] vent The Observers are in constant radial contact with the observatory where seismographs record a sharp increase in earthquake activity tilt and geometer measurements show the mountain is still swelling [Music] base to Delta base to Delta over this is Del I just arrived and SE Howard and over we're getting heavy Tremor yeah she's going wild she's going wild he's putting on quite a show I [Music] [Music] for 5 hours kilaa has been in violent [Music] eruption the height of the fountain is constantly measured [Music] it has reached Heights of 200 to 300 M and is still [Music] Rising smaller vents have opened lava spreads for kilometers around the site [Music] [Music] Hawaiian lava is one of the hottest and most fluid in the world a mighty River of lava has formed the Cascade a curtain of fire is twice as high as Niagara Falls the fountain Soares to Heights of 500 M taller than the Empire State Building [Music] after after 9 hours of activity the fountain begins to subside rivers of lava still feed the falls the main Fountain dies lava flows back into the vent one of the most spectacular eruptions in Hawaiian history has ended National Bureau of Standards wwvh Molly Hawaii next tone begins at 15 hours 20 minutes grenwich meantime [Music]