Results / Deliverables
----- 2020 -----
Activity 1.1: Theoretical documentation on the hardware specifications of the equipment
The following criteria had to be taken into account when defining the hardware specifications of the equipment:
- Possibility of configuration and existence of support for WIFI and LAN communication. Through them, the equipment sends alert and / or receives notifications and alerts from the existing alarm system.
- The existence of a sufficiently powerful processor that allows real-time acquisition from the AD (Analog to Digital) converter and real-time data compression in miniseed format (format used in the seismological community for real-time archiving and transmission) as well as transmission in their real time at the Data Center in Bucharest.
- The possibility of connecting several hardware modules for later uses and new functionalities.
- The interface through which the digital analog conversion board is connected, together with it to allow the sampling of analog data at equal time intervals ("equally sampled data"), because in real-time seismology the data are sampled in this way, for analysis correct in the spectral range of the recorded values
- The possibility to controll some relays to take specific measures in case of detecting an earthquake or receiving an earthquake alert.
- The need to use a Linux-based operating system in order to run the acquisition software called SeisComp
Activity 1.2: Theoretical design of a device that will be able to perform specific actions when notifications are received from the network of EEWS alarm devices as well as the creation of the project web page
As part of this activity, it was designed an entire software package that will run on the platform described above in order to integrate into the existing alarm system at INCDFP. The alarm system communicates via UDP (User Datagram Protocol) packets with the terminals enrolled in the alarm network. The alarm system sends every minute a packet containing the string "HEARTBEAT", announcing that it is functional, and in case of an earthquake packets containing the text "ALARM", followed by information about it. Also in this activity the project webpage was implemented.
----- 2021 -----
Activity 2.1: Optimizing the performance of equipment that allows rapid estimation of the magnitude and location of earthquakes independently in each node using real-time acceleration data, using the regional approach, as well as the "on-site" approach
Following the establishment of the technical characteristics of the equipment, the platform on which the applications developed in this project were implemented is represented by the Raspberry Pi 4 (8 GB RAM version), 32 GB storage and +/- 2g acceleration sensor.
The SeisComP acquisition and processing program (https://www.seiscomp.de/) has been configured within the built system. Within this project, a software application was developed that acquires the data recorded by the acceleration sensor and sends them for archiving to SeisComP.
Activity 2.2: Improve the early warning receiver capable of communicating within the EEWS device network and take specific action when an alert is received or a strong event is detected
During this activity, a software package was developed that runs on each node in order to integrate into the existing alarm system at INCDFP. The alarm system communicates via UDP (User Datagram Protocol) packets with the terminals enrolled in the alarm network.
Within this project, a software package has been developed that allows the enrollment of each equipment in the alarm network. This application aims to provide information to each node about the other existing nodes. Thus, each node (equipment) sends to the other nodes the P-wave detections and their time, in order to decentralize the estimation of the earthquake parameters.
Activity 2.3: Evaluate the performance of node devices within EEWS using historical data
The FilterPicker detector (http://alomax.net/FilterPicker) was used to estimate the detection performance, configured identically to the one applied in the alarm system. Simulations were performed with 2 earthquakes (03/29/2014, Mw = 5.0 and Mw = 5.5) in order to test it.
Activity 2.4: Evaluate the real-time transmission performance of acceleration data and the parameters calculated within the EEWS network
The applications developed during the phase transmit to the other nodes only the calculated parameters (the recorded data can be retrieved after, automatically). Given that each node runs independently of the earthquake detector without transmitting the recorded data in real time to the other nodes, the amount of information transmitted is reduced in volume. For example, the UDP packet sent to the other nodes: "2021-10-26 19: 06: 42.40: PICK Rpi3 2014-01-26 19: 06: 41.33 0.01 -1" tells them that an earthquake detection has taken place at the RPI3 station at 19:06:41. This packet is followed by information about the maximum measured accelerations or displacements, encapsulated in another UDP packet: „2014-01-26 19: 06: 46.29: Rpi3 arrival: 2014-01-26 19: 06: 49.34 Pd_counts: 5.54357 A (cm): 0.00132169 Pv (cm / s): 0.0081961 Tc (s): 0.827304 Alert: n / a. ”. Following the simulations performed, the nodes managed to transmit the parameters calculated within the distributed alarm network developed within this project.
Activity 2.5: Performance and sensitivity tests to evaluate the performance of each node in real time
During this activity, the nodes developed within the project were tested in order to estimate their performances, in terms of hardware stability as well as their performances to detect and evaluate the parameters of earthquakes. One of the most pressing issues was the passive cooling of the equipment processor, without the use of fans or other moving parts that would influence the recordings of the installed sensors. The solution was chosen to use an aluminum case that dissipates the heat generated by the processor and the chipset of the equipment. With the help of this, the tests showed a decrease of more than 30 degrees of the node during the maximum operation, from approximately 85 degrees Celsius in conditions without radiator.
Following the tests on data registered by the national seismic network within INCDFP, the system is able to detect earthquakes with a magnitude of M> 4.0, a performance similar to that recorded by the operational alarm system within INCDFP (ews.infp.ro).
----- 2022 -----
Activity 3.1: Performance tests in order to assess EEWS device node capabilities
Strong motion accelerometers data belonging to Romanian Seismic Network was acquired by the device in order to optimize detection and magnitude estimation algorithms. An evaluation of the alert notification speed was carried out in case of strong events, and the results was compared to the classical, centralized, system. In the same time, continuous data was evaluated in term of data gaps, compression artefacts caused by the acquisition software developed during this project.
Activity 3.2. Sensitivity tests of the EEWS device node
Within the built system, the SeisComP acquisition and processing program (https://www.seiscomp.de/) was configured. Within this project, a software application was developed that reads the data recorded by the acceleration sensor and sends them for processing and storage to SeisComP. If the equipment is located near a seismic station within the National Seismic Network, it can use the data recorded by it. For the detection of P waves, the FilterPicker detector is used (Lomax et al., 2012). This phase detector is suitable to be applied in real-time seismic monitoring as well as in earthquake warning systems. This is an efficient algorithm that applies to continuous data, in real time, and brings information about the polarity and time of detection as well as its amplitude. After tests on continuous strong motion data the detector is able to correctly associate phases down to magnitude Mw=3.6
Figure 1. Lower earthquake magnitude detection limit for the developed equipment.