Rotten egg smell near rivers, betraying the presence of sulphur.
Emergency Procedure
Stay out of harms way-be alert for possible warning signals of imminent eruptions.
Leave the area immediately. Do not waste time trying to save possessions.
Be prepared for difficult travelling conditions. If vehicles get bogged in deep ash you may have no choice but to abandon them, in which case run for the nearest road out of the area. You may be able to hitch a ride.
Avoid areas downwind from the eruption if ash is being expelled.
Cover face with scarf or dust mask to keep any ash and volcanic dust out of the mouth. The combination of ash and acidic gas can cause lung damage. You might try wetting the mask with water, vinegar, or urine.
Protect the eyes with any snug-fitting goggles, safety glasses, or eye wear.
Beware of flying debris-wear any helmet or hat to protect the head. Also wear thick padded clothing for body protection.
Always check for mudflows when approaching a stream channel. A mudflow can move faster than anyone can run and even buildings may not stop one.
Shelter in buildings (other than emergency refuges) ONLY as a last resort. Walls can be crushed by rocks and lava. Roofs are subject to collapse, even from just the weight of ash and debris.
For a fast moving cloud of gas, ash, rock fragments that accompany an eruption you may have only a couple of choices. Either shelter in an underground emergency refuge or hold you breath and submerge yourself underwater in a river, a lake, or the sea. The danger may pass in 30 second or so.
If you are within the fallout area of an eruption keep your activity to a minimum. Evacuate if necessary. Keep posted by local Emergency authorities. Avoid using equipment since fine ash is very abrasive and damaging. Keep a supply of extra air filters for vehicles and homes.
If you are miles away from the volcanic eruption, you may still be effected by the ash fallout due to wind. If your area is blanketed by volcanic ash, stay insided until notified through emergency services that it is safe to come out. Do not drive vehicles through ash as damage can occur to the engine and ash will enter the vehicle. Until ash is safely cleaned up, wear a scarf across the face or a dust or surgical mask.