what is three methods used to assist in the prediction of volcanic eruptions?

Question

Following question,
what is the one of the methods relate to the use of seismic data ?

Answer 1

Non-copyrighted material from USGS Cascades Volcano Observatory website:

Seismicity -- Earthquakes commonly provide the earliest warning of volcanic unrest, and earthquake swarms immediately precede most volcanic eruptions.

Ground Movements -- Geodetic networks are set up to measure the changing shape of the volcano surface caused by the pressure of magma moving underground. Techniques commonly used include electronic distance measurement using a laser light source (EDM); measurement of tilt, both electronically and by repeated leveling of triangular arrays; and standard leveling surveys to obtain elevation changes. Additionally, very simple and inexpensive techniques, such as measuring crack openings using a steep tape, or noting changes in water level around a crater lake, have proven useful in certain situations. Upward and outward movement of the ground above a magma storage area commonly occurs before eruption. Localized ground displacement on steep volcanoes may indicate slope instabliity precursory to mass failure.

Geophysical Properties -- Changes in electrical conductivity, magnetic field strength, and the force of gravity also trace magma movement. These measurements may respond to magma movement even when no earthquakes or measurable ground deformation occurs.

Gas Geochemistry -- Changes in fumarole gas composition, or in the emission rate of SO2 and other gases, may be related to variation in magma supply rate, change in magma type, or modifications in the pathways of gas escape induced by magma movement.

Hydrologic Regime -- Changes in ground water temperature or level, rates of streamflow and transport of stream sediment, lake levels, and snow and ice accumulation are recorded to evaluate (1) the role of ground water in generating eruptions, (2) the potential hazards when hot, energetic volcanic products interact with snow, ice, and surface streams, and (3) the long-term hazard of infilling of river channels leading to increased flood potential.

-- Excerpt from: Wright and Pierson, 1992,
Living with Volcanoes, The U. S. Geological Survey's Volcano Hazards Program: U. S. Geological Survey Circular 1073

Answer 2

Thor - Manowar Black clouds on the horizon great thunder and burning rain His chariot pounding, I heard the heavens scream his call I watched as he shouted To the giants that died that day He hehd up his hammer severe And noted as to Odin for an illustration Thor the effective, Thor the brave weigh down the infidels on your way via your hammer permit none be saved stay to die on that very final day Gods, Monsters and adult men we will die jointly interior the tip God of thunder, god of rain Earth shaker who feels no soreness The powerhead of the Universe Now deliver your in no way ending curse Swing your hammer to crack the sky raise your cape so as which you may fly decrease back to Odin and the Gods on severe And go away this mortal international

Answer 3

Tectonic plate shifts--plates grind against eachother causing the magma underground to push up

Answer 4

if there is a earth quake then there is a possibity of a erpution becase they know the tectonic plates are moving