Learn Volcanic Warning System!
Volcanic Warnings are issued by Japan Meteorological Agency. There
are five Volcanic Alert Levels based on the target area and action tobe taken. These are described using action summary keywords.

Forecast

Level

1 Potential for increased activity

Watch out for volcanic gas.

Watch out for unusual activity.

Some volcanoes gas all the time.

If you notice any unusual activity.

Warning

2 Restriction on proximity to the crater Volcanic lightning

Level

3 volcano

Volcanic lightning
can occur in theplume during aneruption.

If you’re near the mountain or crater.

Level

If you hear a warning while you’re on the mountain,
immediately.

1

Don’t go near the mountain, even if you’re curious.

5

Evacuation

Level

2

No entry

Get away from your home.
Follow instruction from police station,
fire station and village,
Level
town, or city office.
Shockwave from eruption
No entry5

Plume

Pieces of rock and othermaterial that are 20
centimeters or greaterin size are thrown from
erupting volcanoes.
Such debris are known
as ballistic projectiles.

Level

4

When a volcano erupts, the airaround it vibrates, causing a
shock wave. Stay away fromwindows, which can break andcause injury if the shock wave isstrong enough.

Evacuation shelters
are sturdy huts thatcan protect you fromballistic projectiles.

Evacuation shelter

Pyroclastic flow
A pyroclastic flow consists ofash, lava, and gases at atemperature of several hundred
degrees Celsius moving at morethan 100 kilometers an hour!
Pyroclastic flows are extremely
dangerous!

Lapilli
Lapilli are small pieces ofrock and other materials
measuring several
centimeters in diameter.
They are carried by the windbefore falling to the ground.

volcanoes!

If you smell a badodor (volcanic gas) Cover your mouthwith a water-soaked
towel or handkerchief.
 Go inside a building.

Debris flow
A debris flow occurs when large
amounts of water from rain mix
with sand, dirt, volcanic ash,trees, and other debris. Largerocks and other debris candestroy things in the flow’s path.

I geteartrn tele l s h e v olc a nic a v it
i nowing ftand v
caBy k t state o ,olc a n iclyene curr
orrectL

Level

Windrstand volcanoes
ed!
Unlev

Emergency Warning

4

Evacuation of the elderly, etc.

3

Level

Various kinds of phenomena cause damages with volcanic eruptions.

Ballistic projectiles

Level

Bug-outbag

Learn how volcanoes can cause damage!

Wind

Level

Restriction on proximity to theI get !
esvolcanoth lcano cn andothe v an have fu ing
you c e sightsee .
saf d travel
anFalling ash
Fine ash with a diameterof less than 2 millimetersis thrown out of the crater
during eruptions.

Volcanic tremors

Volcanic tremors are the tremors which are caused whenmagma and volcanic gases dissolved in magma come tothe surface. These tremors are also caused when magmaheats groundwater and when magma moves underground.

Isolated-type volcanic tremors

Short-period volcanic tremors with a duration of several
seconds are observed at Aso volcano and called
isolated-type volcanic tremors.

If you see a debris flow
 Immediately move to the second or
higher floor of a strong building.
 Run away from the flow, moving at aright angle from it!

If you see small pieces of rock(lapilli) falling from the sky
 Take shelter in a sturdy building.
 Protect your head using whatever you
can find around you.

y.

I get !
esvolcanoKumamoto Local
Meteorological Office

2-10-1 Kasuga, Nishi-ku, Kumamoto 860-0047

Phone: 096-352-7740 (receptionist)

I get !
es
volcanoLearn about volcanic observations!

Sulfur dioxide is a component of volcanic gas.
To measure the sulfur dioxide emissions, highly precise equipment fitted to cars and ships arethen driven or sailed underneath the plume.
Caution is necessary if there is a sudden change in volcanic gas levels.

Various kinds of observation equipment are installed around avolcano. These devices continuously send data to meteorologicalobservatories so we evaluate volcanic activity from a distance.

Near volcanic
crater
Crater rim
The height of theplume is measured
from here.

This area is hotter than thesurrounding area due to the effectsof heat coming from underground.

GeothermalareaI get !
esvolcanoObserving volcanic gases

Understand volcanic eruptions!
Even when a volcano isn’t erupting, it still gives off volcanic gases
including water vapor, sulfur dioxide and so on.

Measuring distance using GNSS(Global Navigation Satellite System)

Do you know？ Where does magma come from?

When magma rises toward the surface, grounddeformation can be observed.

Magma is created deep underground (at a depth of around 100 to 150
kilometers). Since it’s lighter than around, magma gradually rises
toward the surface over long periods of time. Once magma reaches
the surface, it’s called lava. Volcanoes are made from magma.

We measure the distance between two points (called a ”base line”) that
includes the volcano we’re observing and monitoring. For example the baseline will increase in distance when magma moves from deep undergroundtoward the surface. A volcano’s base line shrinks when it erupts.

Vent

gases and3 Volcanic
other substances aregenerated, pushingmagma close to thecrater and causing thevolcano to erupt.

Crater lake

Seismic waves

In the case of Mt. Aso, water
including groundwater flows into
the crater, creating a green-coloredpool of water at about 50° to 60°C.

Seismic waves growstronger as the magma
approaches the crater.

Magmachamber

2 The number of
Slight deformation of the groundcan be detected with tiltmeter.

Visible cameras
Visible and infrared cameras
provide 24-hour monitoring ofplume color, height, anddirection while watching forballistic projectiles and debris
flows. Sometimes satellites areused to measure plume height.

Thermal cameras
Infrared imaging devices
observe the volcano’s
surface temperature.

Low-frequency microphones
These microphones can tellwhether an eruption isoccurring based onvibrations in the air,even when theweather’s bad.

Scientists try to figureout what magma is
doing based on how
the ground moves up
and down (calledupheaval andsubsidence).

Microphone

Tiltmeters

Upheaval
Subsidence

Scientists use seismometers toinvestigate the location, size,and depth of earthquakes.
These devices tell us whenmagma’s moving, too.

MagmachamberCollecting information

There are 111 active volcanoes in Japan.
The volcanic alert levels are applied at
48 volcanoes as of July 2019.

AnalysisAnnouncements(About the stateof the volcano)

You can check the volcanic alert levels and themonthly volcanic activity report issued by the Japan
Meteorological Agency.
Volcanic Warnings

the magma rises.

Magma chamber

Magma
Rocks and othermaterials melt due to the heat!

The Japan Meteorological Agency issues the volcanic alert levels immediately
if there is an abnormality in the volcano.

Japan
MeteorologicalAgency

1 The mountain swells as

Change inslope

Scientists use precise
equipment to check theslope of mountains.

Seismometers

earthquakes and theamount of gas
increases.

SearchAso Volcano DisasterPrevention Council
Even if Mt. Aso is at volcanic alert level
1, it may not be possible to enter near
the crater due to gas concentration or
weather on the mountain. Please checkin advance from the QR code.

Benefits ofvolcanoes

Environmentallyfriendly geothermalenergyEruption
The volcano emits agray plume including
volcanic ash, ballistic
projectiles and lapilli.
Also, a pyroclastic anddebris flow may be caused.

Volcanic earthquakes
Magma moves upward andgroundwater boils, causing rocks tosplit and become dislodged. Thiscauses earthquakes and tremors(volcanic earthquakes, low-frequency
earthquakes, volcanic tremors, isolated
volcanic tremors, etc.). You may evenfeel the ground shake due to anearthquake.

Even when the volcano
is not erupting…
 White plumes actually consist mostlyof water! These plumes containalmost no volcanic materials suchash.
 Groundwater may be released asheated water.

Hot springs

Good-tastingwater

Volcanoes aren’t all bad! They
also provide many blessingsthat enrich our daily lives.
This pamphlet is a joint project of Kumamoto Prefecture, the City of Aso,
Kumamoto University, Aso Volcano Museum, and Japan Meteorological Agency

This printed matter can berecycled into printing paper.