Study of the Network Impact on Earthquake Early Warning in the Quake-catcher Network Project

The Quake-Catcher Network (QCN) project uses the low-cost sensors, i.e., accelerometers at- tached to volunteers’ computers, to detect earthquakes. The master-worker topology currently used in QCN and other similar projects suffers from major weaknesses. The centralized master can fail to collect data if the volunteers’ computers cannot connect to the network, or it can introduce significant delays in the warning if the network is congested. We propose to solve these problems by using multiple servers in a more advanced network topology than the simple master-worker configuration. We first consider several critical scenarios in which the current master-worker configuration can hinder the early warning of an earthquake, and then integrate the advanced network topology around multiple servers and emulate these critical scenarios in a simulation environment to quantify the benefits and costs of our proposed solution. By using metrics of interest that have a clear scientific meaning for the scope of the QCN project, we show how our solution can reduce the time to detect an earthquake from 1.8 s to 173 ms in case of network congestion and the number of lost trickle messages from 2,013 to 391 messages in case of network failure.