Volcanic eruptions — Module 3 · Phase 3: After

If the family or community was evacuated, do not return simply because:

The return must take place once the competent authorities allow access to the area and in accordance with the conditions they establish.

It may be a conditional return in which it is still necessary to use respiratory protection, avoid certain areas, limit activities, or remain ready for another evacuation.

After an eruption, continue paying attention to communications through the official channels.

Pay particular attention to information about:

An eruption can unfold in different pulses separated by periods of relative calm.

After a first eruptive phase, the following may occur:

For this reason, emergency supplies should not be dismantled immediately; every family and every community must keep the capacity to evacuate again.

One of the most significant risks after an eruption is lahars.

Large amounts of ash and other volcanic material can remain deposited on slopes and later be mobilized by:

Rain

storms

melting snow or ice

overflow

other water sources.

If the authorities issue a lahar warning:

First observe the conditions from outside.

Do not go in if there are signs of:

If there is doubt about the stability of the structure, it must be assessed by competent personnel before normal occupancy is allowed.

A building that remained standing during the eruption is not necessarily still safe.

The structure may have been weakened by a combination of:

• Seismic movements
• ash accumulation
• moisture
• impacts
• fires
• previous damage.

Accumulated ash increases the load on roofs and can become a structural problem, especially once it gets wet.

From a safe location, check whether there is:

Sagging

deformation

cracking

displacement

unusual sounds

damage to beams

significant accumulation.

Capacity depends on numerous factors, including:

• Structural design
• material
• slope
• condition
• load distribution
• density of the ash
• moisture content.

The need to reduce an ash load does not remove the risks of working at height. Removing ash from roofs must only be done when conditions are appropriate and safe procedures are followed.

Climbing onto a roof can carry a danger of:

Before restoring services that have been interrupted, make sure it is safe to do so.

Do not touch:

• Fallen cables
• wet installations
• damaged panels

• affected electrical equipment
• items producing sparks.

If you smell gas or suspect a leak:

• Do not light any flame
• do not smoke
• do not operate electrical switches

• move away from the area
• contact the corresponding service from a safe location.

Cleanup can resuspend particles that had already settled.

Anyone carrying out these tasks must reduce their exposure using:

Respirator suitable for particles

eye protection

clothing that covers the skin

appropriate footwear

gloves (when the task requires them).

N95, P2, FFP2, or equivalent respirators can reduce the inhalation of particles when used and fitted correctly. Remember that these respirators do not protect against volcanic gases.

During tasks that generate dust, people who are particularly sensitive to ash exposure should stay away whenever possible.

This does not mean that every person with asthma must be completely excluded from all activity after an eruption.

Deposited ash must be handled in a way that generates as little dust as possible.

When appropriate, it can be lightly dampened before sweeping or collecting it to reduce resuspension.

The key word is lightly.

Do not unnecessarily soak the ash or use large amounts of water.

Wet ash can:

• Increase considerably in weight
• increase the load on structures
• form deposits that are difficult to remove
• get into drainage systems.

Avoid the indiscriminate use of hoses.

Volcanic ash can block:

• Sewers
• drains
• pipes

• storm-water systems
• treatment systems.

Do not deliberately sweep it toward these systems.

Ash must be collected and disposed of following the instructions of the local authorities.

These authorities may establish:

• Collection points
• deposit areas

• special procedures
• specific containers or methods.

It must not be assumed that household trash bags are always the appropriate method, especially where large volumes are involved.

Do not try to clean the entire home or all community spaces at the same time.

Give priority to:

• Necessary access points
• circulation areas
• areas essential for operations
• spaces used by vulnerable people
• critical equipment
• indoor spaces
• other spaces as needed.

Avoid generating dust in areas that have already been cleaned.

To clean indoor surfaces:

• Use methods that reduce dust dispersal
• use damp cloths or equivalent methods when appropriate
• clean from upper areas down to lower ones
• avoid sweeping aggressively
• control ventilation so outdoor ash does not re-enter
• clean surfaces used to prepare or eat food with particular care.

Conventional household vacuum cleaners can resuspend fine particles or be damaged.

If vacuum systems are used, they must be suitable for fine particles and used according to their specifications.

Do not use compressed air to clean ash from surfaces, clothing, machinery, or equipment in spaces where people could be exposed.

Compressed air resuspends large amounts of particles and increases respiratory and eye exposure.

Ash can get into:

• Computers
• servers
• communication systems
• motors

• electrical equipment
• machinery
• sensitive instruments.

Do not turn on equipment containing significant ash buildup until it has been properly assessed or cleaned.

Cleaning sensitive equipment must follow the manufacturer’s instructions or be carried out by competent personnel.

After an eruption, water must not be assumed safe just because it looks clean.

Follow the guidance of the health authorities and water providers.

If there is a contamination warning:

• Use the alternative source indicated
• keep reserves protected
• do not use potentially contaminated water for drinking or preparing food until receiving instructions
• follow the official procedures established.

Keep in mind that boiling water does not eliminate every possible chemical contaminant.

For that reason, boiling must not be used as a universal solution for any contamination following an eruption.

Check storage containers before using them again.

If ash got in:

• Do not improvise treatments
• follow the health guidance
• determine whether cleaning, discarding, or treatment is needed
• prevent further material from getting in.

In rainwater catchment systems, it may be necessary to temporarily keep water from contaminated roofs from entering the storage tanks.

Discard food that:

• Has been directly exposed to ash and cannot be properly cleaned
• has damaged packaging
• has been contaminated by unsafe water
• required refrigeration and was left too long without a safe temperature
• shows signs of spoilage.

Closed containers must be cleaned on the outside before being opened.

Surfaces and utensils used to prepare food must be cleaned carefully.

If there was a prolonged power outage, assess the safety of refrigerated or frozen food following the health authorities’ guidance.

Do not determine whether food is safe based solely on:

• Smell

• appearance

• taste.

Never taste food to check whether it is still safe.

Keep areas clean and control the entry of ash from outside.

Appropriate filtration systems can help reduce particles in certain spaces.

Check and replace filters when necessary according to the equipment’s instructions.

People with respiratory illnesses must continue reducing their exposure while ash remains suspended.

Ash can cause wear and damage to vehicles.

When it is safe to do so, document the damage before making major repairs.

You can use:

Photographs

videos

inventories

written records

technical reports.

Document, as applicable:

• Structural damage
• equipment
• vehicles
• furniture
• food

• supplies
• installations
• loss of animals
• interruptions to activity.

This information may be necessary for insurance, assistance, aid requests, or later assessment.

After an emergency there is an understandable tendency to try to quickly restore the home or community spaces.

However, do not improvise repairs to:

• Structures
• electrical systems
• gas
• severely damaged roofs
• complex sanitary installations
• dangerous machinery.

Use competent professionals when the nature of the repair requires it.

During recovery, accidents can occur that do not come directly from the volcano.

Pay attention to:

Gas leaks

spilled fuel

damaged electrical installations

generators

unstable structures

broken glass

sharp objects

slippery surfaces

damaged machinery.

Recovery tasks can last days or weeks.

Avoid:

01

Excessively long shifts

02

lifting loads that are too heavy

03

working without hydration

04

unnecessary exposure to ash

05

working alone on dangerous tasks

06

using tools without training.

Organize shifts and breaks.

An eruption can produce:

• Fear
• stress
• anxiety
• difficulty sleeping

• irritability
• a sense of loss
• worry about new episodes.

These reactions can affect direct victims as well as volunteers and community leaders.

Promote:

• Rest
• communication
• support among members

• access to reliable information
• professional assistance when necessary.

These reactions can affect direct victims as well as volunteers and community leaders.

Pay special attention to children, older adults, and anyone who has suffered losses or traumatic experiences.

Do not fully reoccupy the home or completely reopen a community space simply because the building is accessible.

Before restoring normal activities, assess:

• Structural safety
• electricity
• gas
• drinking water

• sanitation
• accessibility
• air quality
• access routes

• communications
• fire systems
• availability of people who can help
• sanitary conditions.

01

02

03

04

Do not immediately dismantle the emergency kits.

Keep available:

Water

respiratory protection

eye protection

radio

flashlights

batteries

medications

documentation

evacuation items.

Volcanic activity can resume.

Once the critical phase has passed, each family and each community must assess how they responded.

The experience should be used to improve the plan.

When possible, document the experience.

This information can be very useful for future training, drills, and plan reviews.

Recovery does not begin when the eruption visually disappears. It begins when the authorities allow it. This process can continue for days, weeks, or longer.