# SeismoCitizen : A project combining seismology and human science approaches based on a deployment of a dense low cost seismic network hosted by citizens

Marc Grunberg, Antoine Schlupp

► To cite this version:

Marc Grunberg, Antoine Schlupp. SeismoCitizen : A project combining seismology and human science approaches based on a deployment of a dense low cost seismic network hosted by citizens. Rencontres scientifiques et techniques RESIF 2019, Nov 2019, Biarritz, France. hal-02446037

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Submitted on 20 Jan 2020

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Distributed under a Creative Commons Attribution 4.0 International License
## Marc GRUNBERG (1) and Antoine SCHLUPP (2)

(1) : EOST-UMS830; Université de Strasbourg/EOST, CNRS; F-67084 Strasbourg

(2) : IPGS-UMR7516; Université de Strasbourg/EOST, CNRS; F-67084 Strasbourg

EOST

École et observatoire

des sciences de la Terre

de l'Université de Strasbourg

et du

<figure><img src="image_2.png" /></figure>

<figure><img src="image_3.png" /></figure>

Laboratoire

Institut de **physique** du **globe**

de Strasbourg | IPGS | UMR 7516

de l'Université de Strasbourg

<figure><img src="image_4.png" /></figure>

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## Introduction

After a first deployment of 8 low cost seismic stations in 2017 around Strasbourg, we launched end of 2018 a multidisciplinary project of citizen seismology called SeismoCitizen. It associates Seismology with Social/Human science research. It is intended to build a real network of observation sites in urban and peri-urban areas, based on internet-connected stations hosted by volunteers citizens, who will also participate in a survey conducted by sociologists.

<figure><img src="image_6.png" /><figcaption>2017 and 2018-2019 low cost stations deployment + 2020 project</figcaption></figure>

## Low-cost stations characterization

During November 2018, the instrumental response of the 27 Raspberry Shake station were simultaneously fully characterized in respect to a reference permanent BB station at the instrumental testing platform of EOST. We observed a constant datation error of about 10 ms on Raspberryshake synchronized by ntp, implying a positive phase shift at HF, dropping to 0 when is GPS synchronized.

<figure><img src="image_7.png" /><figcaption>Restored median transfer function (orange) vs theory (blue).</figcaption></figure>

<figure><img src="image_8.png" /><figcaption>Restored median transfer function if synchronized by ntp (orange) or GPS (blue).</figcaption></figure>

<figure><img src="image_9.png" /><figcaption>Self-noise estimated by the N sensors algorithm on all models.</figcaption></figure>

<figure><img src="image_10.png" /></figure>

Finally, we computed the median self-noise estimate for each model of Raspberryshake using N-channel algorithm, and found significant differences at low frequencies.

(after Bes de Berc, Pestourie, Jund and Broucke, EGU. 2019)

## Construction of the SeismoCitizen sample

-> **Location of participants** imposed by seismotectonic criteria. **Profiles of participant** imposed by sociological criteria.

-> **Call for applications:** Look for 20-25 individuals with diversified profiles, Use of the communication channels of town halls, associations + social networks, mailboxes, local newspaper ad

-> **About 80 responses**

## Deployment in North-East France

The stations have been deployed during the winter 2018-2019 in a intra-continental region, Mulhouse at NE France, with moderate seismicity (Last Mw>4 is the 1980 Sie rentz earthquake, Mw 4.1) but with one of the largest event in western Europa, the 1356 Basel earthquake, Mw estimated at ≈ 6.5. It is an intense industrialized region and one of the French metropolitan regions where seismic hazard level is the highest.

<figure><img src="image_11.png" /><figcaption>Regulatory seismic zoning of France since 2011 (article D.563-8-1 du code de l'environnement)</figcaption></figure>

<figure><img src="image_12.png" /></figure>

Regional seismotectonic context and 2017 seismic network. Red dotted line are suspected active faults. Red star = location of large Basel earthquake of 1356. Blue stars: 2018=M3.5 event (see details hereunder ) and 2019=M2.7 event recorded by the SeismoCitizen network

## Contribution expected from low-cost stations to BCSF-RENASS seismic observatory activities and seismologists

This dense low cost seismic network makes it possible to densify the mesh of the permanent French institutional observation network (RESIF). Thus it improves the French monitoring activities of BCSF-RENASS (characterization of the seismicity as location, depth, discrimination) and products like "shakemap". They will be helpful also for the seismic risk assessment and the data, available for researchers, could also be used to improve the seismological imaging, in particular by passive methods based on the analysis of seismic noise.

<figure><img src="image_13.png" /><figcaption>A Raspberry Shake in the living-room connected at the Internet Box. We add a heavy stone on the top of the station to improve the stability and the contact with the floor.</figcaption></figure>

<figure><img src="image_14.png" /><figcaption>Example of observations based of a ML=3.5 (2018-05-04) before deployment of the SeismoCitizen stations in Mulhouse region.</figcaption></figure>

<figure><img src="image_15.png" /><figcaption>Red dotted boxes highlight the traces recorded by 2 low-cost RaspberryShake stations located at 87 and 104 km of the Ml=3.5 and part of the BCSF-RENASS seismic bulletin.</figcaption></figure>

<figure><img src="image_16.png" /><figcaption>Map of preliminary intensities based on 846 testimonies collected at www.franceseisme.fr for the Ml=3.5. Each dot corresponds to a city and the value is the average of all testimonies. Red star = epicenter</figcaption></figure>

<figure><img src="image_17.png" /><figcaption>Shakemap based on preliminary intensities (numerous observation for France territory) and instrumental data (27 at less than 100 km).</figcaption></figure>

## First analysis of the seismic data
Since 2017, the contribution of a RaspberryShake station to a BCSF-RENASS earthquake location varies from 1 to 80 times with 21 stations to ≥ 10 earthquakes. During the last 10 months, 18 stations contributed to ≥ 10 EQ with 7 stations to ≥ 30 EQ. If we consider induced event, the contribution of individual station is up to 106 times, with 6 stations contributing to ≥ 54 induced event locations. At total, they are 574 individual stations contribution to earthquakes and 574 to induced events location.

<figure><img src="image_18.png" /><figcaption>Map of the seismic stations in operation around Mulhouse in-</figcaption></figure>

cluding the low-cost RaspberryShake deployed (green

triangles) and the RESIF permanent stations (pink triangles).

Seysimicity (circle) is between 2018-12-01 and 2019-11-05.

<figure><img src="image_19.png" /><figcaption>Example of a Ml=2.7 event (red star at left) located</figcaption></figure>

at > 35km from the stations. Black dotted box

highlights the traces recorded by some of the

low-cost stations and part of the BCSF-RENASS

seismic bulletin.

<figure><img src="image_20.png" /><figcaption>Data availability of the low-cost stations deployed by EOST</figcaption></figure>

(each line is a station component): most of the time > 95%.

Vertical lines show transmission difficulty on whole network.

Blue line are either before deployment or due to voluntary

power cut at host home or lost of Internet connection.

<figure><img src="image_21.png" /><figcaption>Map of earthquakes located by BCSF-RENASS using at least one RaspberryShake low-cost station.</figcaption></figure>

<figure><img src="image_22.png" /><figcaption>Map of induced events located by BCSF-RENASS using at least one RaspberryShake low-cost station. They are mainly due to geothermal induced seismicity.</figcaption></figure>

## The Social/Human Science study and interviews (coordination: Philippe Chavot (LISEC-UNISTRA))

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It aims at observing and analyzing the effects of a citizen engagement in scientific research (via hosting a seismometer) on the perception and representation of seismology and micro-seismicity phenomena. Therefore the volunteer citizens will participate to 2 interviews: at the time of the installation and 6-8 months later.

### Organisation of the first set of interviews

**Objective:** Characterize the participants (sociological and cultural approach) and Sensitivity to the environment, industrial projects, science, seismology

**Practical aspects:** Possibility of answering alone or as a couple and Informed consent (ethics) / anonymity of respondents

**Results:** 22 interviews carried out (at end of February), Duration: 30mn to 1h30

-> More than half responded as a couple

<figure><img src="image_24.png" /></figure>

<figure><img src="image_25.png" /><figcaption>Distribution of the sample by gender (n = 34)</figcaption></figure>

<figure><img src="image_26.png" /><figcaption>Distribution of the sample by age group (n = 34)</figcaption></figure>

### Interview guide (a main question + several reframing questions per thema)

**Issue 1. Knowing you better:** Can you tell us a little bit about you? (academic and professional background / associative affiliation / digital equipment)

**Issue 2. Territory perception and interest in environmental & industrial issues:** Have you the feeling to be an Alsatian person? (time spent in the region / what best characterizes this region / what you do not like in this region / interest in industrial heritage and environment)

**Issue 3. Perception of science:** What is science for you? (part plays by science in society / name the the most scientific discipline / place of science in your school and professional career).

**Issue 4. Perception of seismic hazards and seismology:** Have you ever felt any seismic activity? (how are you sure that it was a seism / search for information about this seism / is this a worrying topic)

The seismocitizen project team: Antoine SCHLUPP (2), Philippe CHAVOT (3), Marc GRUNBERG (1), Maxime BES-DE-BERC (2), Hélène JUND (1), Fanny AJAK (1), Jérôme VERGNE (2), Frédéric MASSON (2), Jean SCHMITTBUHL (2). (3) : LISEC-EA 2310; Université de Strasbourg/EOST, CNRS; F-67084 Strasbourg, France

Acknowledgements: The authors thank Fanny Ajak, Christine Heimlich and Cirille Bodin who contributed during November 2018 - February 2019 period to the call of applicants and the interviews. The projet is supported by the CNRS (Interdisciplinary mission) and the LabEx G-eau-Thermie Profonde of UNISTRA.