Phones & Radios

Communication is a vital part of everyday life and is critical during emergencies. Radio and telephone communications are extremely vulnerable to disruption during a volcanic ashfall and may become temporarily inoperable in areas affected by ash.

The disruptions to communications include interference to radio waves due to atmospheric conditions, overloading of telephone systems due to increased demand, and direct damage to communication facilities. Indirect impacts can also occur from disruption to electricity supplies or when maintenance workers are unable to travel to remote sites.

Overloading of systems

During most natural disasters, telephone and radio communications are susceptible to overloading by public and emergency services use. Response organizations report frequent overloading of their telephone lines even in cases where the general system remains operative. To reduce loading on the network, members of the public should avoid using phone lines during an eruption.


Large quantities of electrically charged ash can be generated in an eruption column. This charged ash can cause interference to radio waves and render radio and telephone systems inoperative. However, this has been very rarely observed. There are many examples of radio and telephone communications continuing to function around an erupting volcano and in areas receiving ashfalls.

Damage caused by ash

Most modern telephone exchanges require air-cooling systems to keep electronic switching gear below critical temperatures. Exchanges with external air-cooling systems are thus vulnerable to over-heating if these units fail or are switched off (due to ashfalls), even if the exchange itself is sealed. Some exchanges are sealed to keep out corrosive geothermal gases such as H2S. However, any ash entering telephone exchanges can cause abrasion, corrosion, or conductivity damage to electrical and mechanical systems.