Middle term report of the seismic experiment TOMO-ETNA, MED-SUV

Size: px

Start display at page:

Download "Middle term report of the seismic experiment TOMO-ETNA, MED-SUV"

Ashlee Holt
5 years ago
Views:

Middle term report of the seismic experiment TOMO-ETNA, MED-SUV Last July 6 th, 2014 the active seismic experiment TOMO-ETNA, MED-SUV reached its middle term period with the arrival of the Sarmiento

At his moment all seismic stations, permanent and portable (short period and Broad Band) were deployed and recording the natural and induced signals generated by the air-guns of the Sarmiento de

a) Sarmiento de Gamboa activities. Every working day, a resume of the onboard activities is reported by a diary written in English, Italian and Spanish and provided by Mrs.

1 Middle term report of the seismic experiment TOMO-ETNA, MED-SUV Last July 6 th, 2014 the active seismic experiment TOMO-ETNA, MED-SUV reached its middle term period with the arrival of the Sarmiento de Gamboa vessel to the Island of Stromboli. At his moment all seismic stations, permanent and portable (short period and Broad Band) were deployed and recording the natural and induced signals generated by the air-guns of the Sarmiento de Gamboa. The description of the experiment can be divided in three parts; a) the activities of the Sarmiento de Gamboa vessel; b) the activities of the Galatea vessel; c) the terrestrial work. a) Sarmiento de Gamboa activities. Every working day, a resume of the onboard activities is reported by a diary written in English, Italian and Spanish and provided by Mrs. Eloisa Claude and with the support of the chief of the marine campaign, Prof. Carrion. These diaries can be consulted in the following link This period of working was performed under the support of the project Eurofleet2. Between June 25 th to 27 th the activities were focused in the deployment of the 15 OBSs belonging to the UTM-CSIC (Spain) research center. In the following table we report the position, timing and depth of every OBSs deployed. Deployment time OBS Latitude Longitude Depth June 25 th, 21:00 SPA-I o N 015 o E 1732 June 26 th, 00:17 SPA-I N E :00 SPA-I N E :45 SPA-I N E :19 SPA-I N E :43 SPA-I N E :33 SPA-I N E :41 SPA-I N E :06 SPA-I N E :30 SPA-I N E 1995

17:19 SPA-I-11 37º 26.9060 N 15º 23.4047 E 2032 19:06 SPA-I-10 37º 29.7606 N 15º 19.

8829 N 15 25.8559 E 2230 13:33 SPA-I-15 37 13.5011 N 15 22.2036 E 1732 Figure 1.

The shooting period started on June 27 th at 17:25 h GMT with a series of low intensity

Before every shooting process, the marine biologist on board has initiated the observation

2 17:19 SPA-I-11 37º N 15º E :06 SPA-I-10 37º N 15º E :12 SPA-I-09 37º ' N 15º ' E 1910 June 27th 11:19 SPA-I N E :33 SPA-I N E 1732 Figure 1. Two moments of the OBSs deployment process. The shooting period started on June 27 th at 17:25 h GMT with a series of low intensity shoots in intervals of 30 seconds. Before every shooting process, the marine biologist on board has initiated the observation activity in order to monitor the presence of marine cetaceans in the area. The following pictures illustrate the process of the deployment of the air-guns in the sea. Figure 2. Two moments of the air-guns deployment process.

$In the following days the refraction shooting period was performed in$

3 Figure 3. An example of the bubbles originated in the surface of the sea when the air-guns are shooting. In the following days the refraction shooting period was performed in the Ionian and Tirrenian sea. Figure 4. View of Mt Etna from the oceanographic research vessel Sarmiento de Gamboa.

4 Contemporaneously to the shooting process, onboard started a series of seminaries on courses with different arguments associated to Geophysical Volcanism, Seismic Data Processing, Application of the Geophysical Techniques, Marine Life and others. Figure 5. An example of one seminar onboard. From June 27 th to July 2 nd this shooting process was performed in the Ionian Sea, and from July3th to 6 th in the Tyrrhenian Sea. The lines performed in both seas are illustrated in the following pictures. Figure 6. Shooting lines performed in the Ionian sea.

The end of this first period of work was in the island of Stromboli were the personnel on board had a day of

5 Figure 7. Shooting lines performed in the Tyrrhenian sea. During the shooting lines other geophysical and marine data were acquired, mainly high definition bathymetry. The end of this first period of work was in the island of Stromboli were the personnel on board had a day of meeting with part of the onland working group in order to exchange experiences and to planify the second phase of the experiment. Figure 8. Sunset over the Alicudi and Filicudi Islands.

6 Figure 9. Boat transfer from the Sarmiento de Gamboa.. Figure 10. Three examples of the present volcanic activity at the Island of Stromboli.

b) Galatea activities. The activities performed onboard of the Hydrographic vessel Galatea of the Italian Navy are included in the time-interval between June 25 th and July 3 rd.

submarine robot. The OBSs deployment was performed during the days June 25 and 26 th, and 12 OBSs were deployed, 2 with Broad Band seismometers and 10 of short period.

7 b) Galatea activities. The activities performed onboard of the Hydrographic vessel Galatea of the Italian Navy are included in the time-interval between June 25 th and July 3 rd. These activities includes three objectives: deployment of the Italian OBSs; Marine magnetic survey; and sampling of different geochemical aspects of some Sea Bottom sites of interest using a submarine robot. The OBSs deployment was performed during the days June 25 and 26 th, and 12 OBSs were deployed, 2 with Broad Band seismometers and 10 of short period. Five (one BB) of them were deployed in the Tyrrhenian sea and seven in the Ionian (one BB seismometer). The following pictures illustrate the deployment process of the OBSs. Figure 11. Two moments of the OBSs deployment onboard of the Galatea vessel. In the following map we illustrate the path followed by the Galatea vessel during the OBSs deployment period and the position where the OBSs were deployed in both seas, Tyrrhenian and Ionian.

8 Figure 12. Path followed by the Galatea vessel during the OBSs deployment period and the position where the OBSs were deployed in both seas. The second experiment was the use of a submarine robot to recovery some samples of high interest from the point of view of volcanological and petrological aspects. This work was done contemporaneously with the marine magnetic survey. Robot was used in the period June 28 th and July1st. The following map show the places where the robot was dived and some pictures before to dive the robot and the vision from the tele-camera incorporated in it.

Figure 13. Places where the submarine robot was dived. Figure 14.

A very dense grid was designed in order to obtain a high resolution magnetic image

9 Figure 13. Places where the submarine robot was dived. Figure 14. The submarine robot and an image obtained when it was dived. Finally the magnetic profile was performed in an area of high interest due to its potential influence on volcanic processes. A very dense grid was designed in order to obtain a high resolution magnetic image of the sea bottom. This survey was done between June 27 th and July 3 rd. The following map show the magnetic grid and some moments of the deployment of the magnetometer.

10 Figure 15. The grid used for the magnetic marine profile.. Figure 16. The magnetometer onboard of the Galatea vessel and on the sea.

11 c) Terrestrial activities. In order to perform a high velocity deployment of seismic stations the terrestrial team was divided in four groups located in different villages of Sicily Island. Each group has at least two rented cars, a station wagon and a van, to move from their accomotation pnace to the selected seismic stations. In case of the groups located in Catania, the support of the INGV-Catania (Osservatorio Etneo) provided several out roads cars and some vans. For the case of the Etnean group of Milo, some out roads from INGV-Catania and Rome were used as support. The Broad Band stations (20) were deployed in specific selected places of the GPS network and of the old permanent short period seismic stations. These stations were deployed by the GPS and Seismic technician of the INGV-Catania. On July 27 th the 100% of the seismic instruments were deployed successfully and running. As indicated in the previous report, each team had a specific indication of how to arrive to the selected sites. This indication contains a picture taken from Google Map with a mark of the site, coordinate of the site, a clear indication of how to arrive, the persons who visited previously the site and potential person of contact to entry in the place. Each car was equipped with a basic set of tools, communication equipments and other. These instruments are: - A mobile smart phone with Italian card, including internet connection and a GPS application. - Four halogen headlamps with batteries of replacement. - A toolbox with various kinds of screwdrivers, pliers, wrench, scissors, electrical duct tape, duct tape, gloves, compass, level and a tester. - Two Picks, two shovel and two hoes. - A fluorescent jacket for each person with identification of the project, INGV and UGR. - Two back-packs of 50 liters of capacity to transport sensors and batteries. - Their correspondent number of data logger, seismometers and batteries, including batteries of replacement for the data logger. - A folder with the information of their respective stations (instruction of use, replacement and maintenance), sites and routes to arrive to them. - A clear identification sheet that the car and the persons in it belonging to the INGV- Catania and to the MED-SUV project and TOMO-ETNA experiment. As a resume of the number of seismic stations deployed we have: a) Villafranca Group: 14 short period seismic stations b) Randazzo Group: 18 short period seismic stations c) Milo (Etna) Group: 12 short period seismic stations d) GPS technicians: 8 Broad Band seismic stations e) Seismiological technicians: 8 Broad Band seismic stations f) Catania Group: 4 Broad Band and 36 short period seismic stations. At the present, in the middle of the experiment it is calculated that more than Km have been driven including the phase of search of potential places to install seismic stations. After the phase of installation of the seismic stations, each group developed activities of maintenance and control of

them. These activities are focused mainly in the controlling of the proper operation of the seismic stations and the change of the batteries in the day 10 after the deployment of the seismic station.

12 them. These activities are focused mainly in the controlling of the proper operation of the seismic stations and the change of the batteries in the day 10 after the deployment of the seismic station. In the following map we illustrate all the seismic stations deployed in the experiment and identified according with the different teams involved in their deployment. Figure 17. All the seismic stations deployed in the experiment, including the permanent seismic network of the INGV, and identified according with the different teams involved in their deployment. As routine procedure, every day the operation co-ordinator, Dr. Janire Prudencio, contacted with every headquarter to indicate the activities of the day, potential changes, recovery information and potential problems, including potential help of the other teams to every site. As an example of the initial indications of how to arrive to the sites and the final installation of the seismic stations, we report the following pictures. In the first two pictures we present the initial indication, and in the next ones the pictures of the arrival of the team, the installation procedure and how the station finished.

21 To finalize the present report we would like to show some examples of registration of the shoots at different stations of the permanent seismic network of the INGV. An example of the initial soft phase of the shooting process recorded at the HAGA seismic station located in the Augusta Bay, at the south of Etna. An example of the shooting process recorded at the HLNI seismic station located near of Lentini village. An example of the shooting process recorded at three seismic stations located in the Etnean area. An example of the shooting process recorded at Vulcano Island (IVPL) seismic station and other located in the north of the Sicily Island.

Beginning active seismic experiment TOMO-ETNA, MED-SUV

Beginning active seismic experiment TOMO-ETNA, MED-SUV Last June 16 th, 2014 the active seismic experiment TOMO-ETNA, MED-SUV officially started with a preparation of the seismometers to be deployed in