Post-Earthquake Emergency Communication in Disconnected Areas

After an earthquake the cellular network is lost in two stages: the instant overload and lock-up that follows the first tremor makes the network unusable within 1-5 minutes, and as the backup power of base stations runs out the area falls into complete physical silence within 2-4 hours (120-240 minutes). From that moment on, BosNets keeps communication running without any additional infrastructure being built on site: the team is on the network about 5 minutes after the devices are handed out, and messages, locations and emergency alerts travel without touching the cellular network at all. In the 6 February 2023 earthquakes, 2,800 of the 6,350 base stations belonging to two operators in the region had gone out of service within seconds. This application note describes step by step how the system is deployed in a disconnected area after an earthquake.

Why does the network collapse after an earthquake?

The phone in our pocket is not a communication device on its own; it is only an endpoint that connects to the nearest base station. The real work happens in the infrastructure behind that station, and keeping it standing depends on two things: electricity and a backhaul link to the core network. An earthquake usually cuts both at the same time.

The loss happens in two stages. The first is in the opening minutes: because everyone tries to call and message at once, the stations still standing are overloaded and lock up. A network that works in theory becomes unusable in practice within 1-5 minutes. The second stage is power: stations with backup batteries last a few hours, those with generators until the fuel runs out. After roughly 2-4 hours (120-240 minutes) the area falls into complete physical silence and the coverage area is wiped off the map.

The first hours, when search and rescue teams need communication most, fall exactly in this window. That is why the question to ask in a disaster plan is not when the network will come back, but which system works while it is gone.

Deployment steps

1. Handing out the BosMag devices

Every team member entering the field is given a BosMag. The device measures 7 × 6 cm and weighs 200 grams; it attaches to the back of the phone with its magnetic mount and pairs with BosApp over Bluetooth. There is no separate setup step, cabling or frequency application — once the devices are handed out the team is on the network within about 5 minutes. The devices find each other and form a mesh network; every device in the team is also a relay, so the covered area grows as the team spreads across the collapse site.

2. Extending coverage with BosBase

If the site is very wide, if there are valleys and ridges in between, or if the coordination centre is far from the collapse area, the BosBase relay station is brought in. It reaches 20 km with its larger antenna, draws its power from solar energy and needs no fixed mounting: it is left at a high point or placed on a vehicle roof to become a mobile relay. No generator, cable or mains electricity is required.

3. Location, tasks and emergencies through BosApp

A team member sends written messages, shares their location and sees the others on the map. With the offline map feature the map of the area can be downloaded in advance, so it opens without internet; position is produced by the GNSS sensor inside the device to 1.5 m accuracy, meaning it does not depend on a network. For being trapped under rubble, falling or being unable to reach a phone, there is an emergency button on the device: when pressed, the identity and current location of the person pressing it appear on every screen in the network.

4. What the coordination centre sees

The BosLog screen at the centre gathers every device in the field, every shared location and every marked point onto a single map. Tasks are assigned, the position of each team is tracked, and all traffic is recorded with time stamps. Post-operation reporting and incident analysis are carried out on that record.

5. When the network returns

When coverage comes back in part of the area, the system automatically works in hybrid mode: phones with a network send their messages over the internet while the others continue over the mesh. On a device that re-enters coverage, the messages accumulated in the meantime are synchronised with the server, so the operation history stays intact. The user changes no settings.

Technical values

Range, battery, dimension, protection, position and frequency figures are the manufacturer values published on the BosMag and BosBase product pages. Hop count is taken from the BosNets device software v3.5 configuration. Setup time and the recommended device density are BosNets field measurements. The base station data refers to the 6 February 2023 earthquakes; the network collapse timings are the ranges generally accepted in disaster communication. Last updated: 3 September 2026.

Field experience

BosApp and BosLog were run inside a real search scenario for four days at the AFAD Drone Search Competition organised by the Turkish Ministry of Interior Disaster and Emergency Management Presidency in Samsun on 17-20 August 2026. AFAD teams from 81 provinces took part. Search and rescue personnel in the field marked the location of the object they detected by drone on the map through BosApp; the provincial AFAD directors inside the truck used as the Disaster Coordination Centre saw the same markers live on the BosLog map. The deviation between the marked point and the real position of the object was measured. Over the four days, more than 100 AFAD staff registered for BosApp.

This was a controlled competition environment rather than a disaster deployment; even so, the system’s real job between the coordination centre and the field — marking locations and following them on a single screen — ran with real users inside a real search workflow. The detailed notes from the four days are published on the blog.

Beyond that, the system has been run in coordination scenarios with the teams of senior officials from civil public institutions and military organisations. Institution names are not published on this page; details are shared as part of a technical briefing.

Frequently asked questions

Why does the cellular network collapse after an earthquake?

In two stages. First instant overload: because everyone tries to call and message at the same time, the network locks up within 1-5 minutes. Then power: a base station needs both electricity and a backhaul link to the core, and an earthquake cuts both at once; stations with backup batteries last a few hours and those with generators until the fuel runs out, so the area falls into complete physical silence within 2-4 hours (120-240 minutes). In the 6 February 2023 earthquakes, 2,800 of the 6,350 base stations belonging to two operators in the region went out of service within seconds.

Does the system need to be set up in advance to work in the field?

No. Once the devices are handed out the team is on the network within about 5 minutes: the network is up as soon as the device is attached to the phone and paired with BosApp. No mast, cabling, SIM card or frequency allocation is required.

How long do the devices last on a collapse site with no electricity?

BosMag works for 48 hours while active on the network; heavy message and location traffic shortens that, and the device can be charged in the field. BosBase draws its power from the sun and keeps working through the night on its internal battery.

Can an organisation run its own closed network?

Yes. When a dedicated closed network is set up, communication data is kept on the organisation’s own server and the organisation decides who may join. The structure works the same way whether or not there is an internet connection.

Let us see the system working on your own site, with your disaster unit or your search and rescue team.

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