openeew/detector

Earthquake detection for OpenEEW

This is a simple Docker configuration to startup a new OpenEEW detection system. It ingests data from OpenEEW sensors via an MQTT broker, and triggers for individual sensors using a detection method. These events are then sent to a multi-station logic script that checks time and distance proximity for sensors before declaring an earthquake.

Quick start

Install https://www.docker.com/get-started and run a detector container with the following command.

shell
docker run \
  --interactive \
  --tty \
  --detach \
  --env username=admin \
  --env password=admin \
  --publish 1883:1883 \
  --name openeew-detector \
  openeew/detector

You can change the port published to host and the credentials. In the following example the detector listens on port 8080 and the username and password used for authentication are foo and bar.

shell
docker run \
  --interactive \
  --tty \
  --detach \
  --env username=foo \
  --env password=bar \
  --publish 8080:1883 \
  --name openeew-detector \
  openeew/detector

You can also omit the username and password parameters but that would be a less secure option and would allow anyone to publish data to your detector. This setup is primary meant for development.

Build your own Docker image

For developers only. Apply the changes to the Dockerfile and run the following command.

shell
docker build --tag openeew/detector:dev .

Then run a development container:

shell
docker run \
  --interactive \
  --tty \
  --detach \
  --publish 1883:1883 \
  --name openeew-detector-dev \
  openeew/detector:dev

Simulate sensor data

Start a container as indicated above and then run the following on the host machine:

shell
cd scripts
python3 sensor_simulator.py --username admin --password admin --port 1883

Components

!MQTT

Incoming sensor data

Sensor data

The data comprises records of acceleration in three channels representing sensor movement in the space. The channels are orthogonal (90 degrees from each other), two components are horizontal, x and y, and one vertical, z. The units are gals, centimeter per second squared.

MQTT Broker

OpenEEW sensor data is ingested via a https://mosquitto.org/ with the topic /traces.

Detection Algorithms

Single sensor process - STA/LTA

First we run a Short-Term Average/Long-Term Average (STA/LTA) algorithm .This method is widely used to identify any disturbances in the signal (such as earthquakes) and determine the time when an event starts.

!STA/LTA x component")

The algorithm takes each channel independently (x, y and z) and applies the moving average using two windows and returns the ratio as a function. Based on the part of the signal where there is no earthquake, a trigger level can be defined.

Single sensor process - Shaking level

The maximum acceleration, or Peak Ground Acceleration (PGA) (x**2 + y**2 + z**2)**0.5) is used to determine the level of shaking that needs to be updated after a triggering using the three components at the same time.

The output from this process is sent as a value (PGA) using the topic /pga-trigger.

To be added.

Detection Implementations

Python

This repo contains python scripts which subscribes to /traces and runs 2 processes against each incoming message; an STA/LTA, and a PGA trigger.

JavaScript

The https://github.com/openeew/openeew-nodered contains an example of how to implement the PGA algorithm in JavaScript.

Multi sensor process - Earthquake confirmation

To be added.

Output

To be added

Authors

• Grillo
• https://github.com/EgidioCaprino

Enjoy! Give us https://github.com/openeew/openeew-detection/issues if you have suggestions on how to improve this information.

License

This information is licensed under the Apache Software License, Version 2. Separate third party code objects invoked within this code pattern are licensed by their respective providers pursuant to their own separate licenses. Contributions are subject to the Developer Certificate of Origin, Version 1.1 (DCO) and the http://www.apache.org/licenses/LICENSE-2.0.txt.