2.3 Support for Campaigns

Table 2-5: Campaigns Supported for FY96 with Field Engineer

Emergency response describes the response to a natural hazard, such as an earthquake or volcanic eruption. Planning is condensed and more staff resources work to support the project in a shorter time frame. The UNAVCO Boulder Facility has provided support to emergency requests since 1992 when the Facility sent staff and equipment to Turkey in response to the magnitude 6.9 Erzincan Earthquake (GPS measurements of crustal deformation in the Eastern Mediterranean, 1996 Science Snapshots) and to Southern California in response to the magnitude 7.4 Landers Earthquake in California (Coseismic displacements of the 1992 Landers earthquake sequence, 1996 Science Snapshots). More recently, UNAVCO has responded with support to the magnitude 7.8 Guam earthquake in 1993 (Catching earthquakes with GPS, 1996 Science Snapshots) and the magnitude 7.8 October 1995 Manzanillo subduction earthquake (GPS strain measurements above the subducting Rivera and COCOS Plates, 1996 Science Snapshots).

South Soufriere Hills Volcano Project, Montserrat, British West Indies, (NSF-EHR and MRCE)

A phreatic eruption sequence began on July 18, 1995 within English Crater of the Soufriere Hills volcanic center in Montserrat, BWI (Figure 2-4). Magma breached the surface in late September, ultimately producing a dome composed of amphibole-bearing andesite. Growth of the dome accelerated during late November 1995. The UNAVCO Boulder Facility responded to an emergency request for support with GPS systems and a field engineer in early October. Due to the limited availability of pool equipment at the time of the request, UNAVCO coordinated the use of three Trimble 4000SSE systems which belong to the University of Wisconsin. The receivers were shipped from the Boulder Facility to Puerto Rico where the UNAVCO Engineer, Brett Baker, deployed them to Montserrat Island. Brett was in the field for one month following his immediate deployment, with another month spent in follow-up support. Upon his arrival in Montserrat, Brett assisted with the modification of the local network which consisted of six sites of a pre-existing conventional triangulation network on and around the volcanic center. From October 10 to December 29 the receivers were moved among the sites, with individual site occupations of 8-10 hrs/UTC day. Brett managed the network while in the field (Figure 2-5), and trained several operators and an agent to take over the network operation upon his departure.

Figure 2.4. Soufriere Volcano (Radio modem links established in October 1995 to base station at MVO are indicated).

Figure 2.5. Montserrat Volcano Data Collection by UNAVCO Engineer, Brett Baker.

Conditions were challenging during this deployment due to hazardous work conditions. An eruption which occurred during the project trapped several phone company workers in a building near the summit close to a GPS site for several hours. Hurricane Roxanne was also in the area at this time causing severe weather on the island. As a result of the rain there were many landslides across the road, which cut off access to different sites near the end of the project.

In order to aid in hazard assessment, Brett processed the GPS data in near real-time using Trimble GPSurvey software with broadcast emphemerides to determine relative baseline changes. Subsequent processing using GIPSY software, precise emphemerides, and 20-25 globally distributed reference sites confirmed the relative baseline changes calculated based only on sites within the local network (GPS measurements of surface deformation during initial dome growth at Sufriere Hills, Montserrat, BWI, Spring, 1996 AGU). Linear fits to the daily radial component site positions obtained from GIPSY for all six sites indicate subsidence at between 19 to 30 cm/yr. Local horizontal site velocities are greater than 12 cm/yr ENE, except for the Chance's Peak site located <0.5 km away from the dome and at the topographic maximum of the volcanic edifice, which is greater than 34cm/yr WSW. The geodetic data are broadly consistent with a combination of evacuation of a shallow crustal magma body, complex intrusion of a shallow dike, and downslope movement of the volcanic flank.

Central and South America Project (CASA) (NSF-Geophysics and NASA)

Displacement rates have been determined for the wide plate boundary in Central and South America from GPS measurement campaigns supported by UNAVCO in 1988, 1990, 1991, and 1994 (Table 2-6). These results show rapid subduction at the Colombia (50 mm/yr), Middle America (72 mm/yr), and Ecuador (70 mm/yr) trenches (Arc-continent collision and oblique subduction in the north Andes, 1996 Science Snapshots). In the first three months of 1996, the CASA project extended its work with a large campaign and the installation or reconnaissance of three continuous GPS stations in Panama, Colombia, and Ecuador. The campaign was funded by NSF-EAR and the continuous station installations were supported by NASA-DOSE. Repeat GPS measurements of the 30 primary CASA stations in five countries (Colombia, Ecuador, Costa Rica, Panama and Venezuela) were conducted, with a UNAVCO field engineer providing project oversight for work done in Colombia and Ecuador. Data were collected from over 240 sites in Colombia and Ecuador (Figure 2-6).

Figure 2-6. CASA Densification Sites.

Table 2-6: UNAVCO Facility Support to CASA Projects

The project was designed around the precise point positioning (PPP) processing strategy, where feasible, to maximize the tectonically useful geodetic data collected and to reduce costs. The PPP processing strategy takes advantage of a strong network of permanent stations so it is not necessary to collect data simultaneously, which reduces the number of receivers and simplifies logistics. Where convenient, GPS data were collected simultaneously, but this did not dictate the project planning. Data were collected over a three month period in Colombia, one month in Ecuador, and less than one month in the other countries. Data collection in Colombia and Ecuador was coordinated with Paul Lundgren's DOSE-funded Costa Rica Project and with work conducted by the University of Zulia in Venezuela.

Karl Feaux, the UNAVCO field engineer for CASA, provided project management and field support for the campaign and for the installation of two continuous stations, one in Colombia and one in Ecuador. The support was comprehensive, including coordinating NASA and NSF-funded portions of the project, and working closely with the JPL liaison, Steve Fisher, and the investigator, Jim Kellogg. As the PI was in the field for only a brief time during the project, Karl provided planning oversight for all aspects of the project including data collection and negotiating with in-country collaborators. He managed the financial negotiations and oversaw the financial expenditures, organized and conducted training for all operators and two agents[4], conducted site reconnaissance at two locations, maintained and repaired both Trimble and Turborogue receivers, and oversaw the data management and archiving for 121 days of data from 245 sites.

Karl Feaux provided two weeks of training in Colombia and Ecuador for twenty-four operators. Twelve Trimble 4000SSE UNAVCO pool receivers were deployed to support measurements in these countries. Planning, logistics, financial management, and data management support were organized and overseen by Karl in coordination with two agents (Hector Mora and Bob Trenkamp). Karl directly managed the organization and planning at the start of the project in both countries and the final data management and return shipping in Ecuador. Trenkamp and Mora coordinated the final data management and return shipping from Colombia, working with UNAVCO staff at the Facility. The equipment worked well throughout the project with one receiver malfunction identified by Karl using the UNAVCO QC program and the repair of one set of solar panels. When necessary, Karl visited sites for either reconnaissance, training, or to provide operator assistance. For example, at the Cartegena site he negotiated with the landowner to have the 30 foot trees which had grown up around the site since the last campaign in 1994 cut down.

Karl provided three months of support in the field, from January 3, 1996 to April 8, and another two and one half months in pre-and post-planning activities. A second field engineer, Dave Mencin, provided two months of support with planning and installation of the NASA/DOSE continuous stations. The Facility continues to support these stations under the NASA/DOSE program, including an engineer visit to the continuous station in Ecuador to resolve equipment and communications problems.

Jalisco Block Project (NSF-Tectonics)

The Jalisco region of western Mexico lies above the independently subducting Rivera and Cocos plates, which move about 20 mm/yr. relative to each other where they subduct beneath the continental margin. To lay the foundation for measuring interseismic strain that can be used to study the regional neo-tectonics and to establish a benchmark network in the event of a major subduction earthquake, initial measurements were made in March 1995 at ~20 sites in western Mexico. Only seven months later, the Mw=7.8, October 9, 1995 Manzanillo subduction earthquake, which was the first significant earthquake to have ruptured the Rivera subduction zone since June of 1932, occurred. (GPS strain measurements above the subducting rivera and Cocos Plates, 1996 Science Snapshots).

In March 1996, the UNAVCO Boulder Facility supported a seven receiver project which consisted of a reoccupation of the 1995 survey and the measurement of nine new sites. Three of the receivers used are owned by the Universitaria Nacional Autonomia de Mexico (UNAM), which were sent to the UNAVCO Facility prior to the campaign for a maintenance check. Brett Baker, the UNAVCO field engineer, provided one month of in-field support to the project with another month and a half of pre- and post-field support. Chuck DeMets, the principal investigator, was in the field during the data collection and worked with Brett to coordinate the occupation schedule and logistics support. Brett's role was centered around field engineering and operator-specific tasks, including site reconnaissance. Brett managed the equipment preparation, shipping, customs clearance and return shipping, conducted operator training classes in both Spanish and English, operated four sites including the fixed base station, and oversaw the data management and archiving.

Ten days prior to the start of the campaign and DeMet's arrival, Brett flew to Guadalajara to select and install nine campaign monuments throughout the state of Jalisco. Brett arrived early to oversee clearance of the equipment through customs which has become more difficult due to recent changes in the law, including NAFTA[5] and Mexico's attempts to curb graft[6]. Mexican authorities conducted two separate inspections of all nineteen boxes of equipment being imported.

The data collection strategy was based on one fixed base site with other receivers roving on independent schedules to collect data. Reliable operation of the base site was key to this strategy. Brett managed this site along with one other during the data collection period. At the end of the project, he managed the data collection at three sites which were missed during the main campaign. He also oversaw the data management including data verification and quality checking. Once back at the Facility, Brett worked with UNAVCO archive staff to transfer the data and metadata to the archive.

Eastern Mediterranean Project (NSF-Geophysics)

Crustal velocity estimates for the period 1988 - 1994 are providing constraints on the kinematics of crustal deformation in the Arabia-Africa-Eurasia continental collision zone, and accordingly on the rheology of the continental lithosphere and the forces responsible for active deformation (GPS measurements of crustal deformation in the Eastern Mediterranean, 1996 Science Snapshots). The UNAVCO Boulder Facility has supported six campaigns in the Mediterranean region since 1988 to collect GPS data to support this research (Table 2-7). In 1996, a seven week campaign and two continuous station installations were conducted to continue this work. The project consisted of large field campaigns in Turkey, Georgia, Russia, Egypt, Armenia, Israel, and Bulgaria with approximately 500 site days of data collection. Twenty-three receivers from the UNAVCO pool were used on this project along with nine from collaborators in Bulgaria, Turkey, and Russia.

The UNAVCO field engineer, Dave Mencin, managed all negotiations and planning for activities in Georgia, Russia, Egypt and Armenia. Rob Reilinger, the principal investigator, managed the work in Turkey with regular contact with UNAVCO staff in Boulder. In-country collaborators supported measurements in Bulgaria and Israel. Dave staged his work from Georgia, which required him to work independently without outside support due to poor communications and in-country infrastructure. Dave visited Armenia and Egypt to conduct training and planning for continuous station implementations. He also visited southern Russia during the campaign to trouble-shoot and repair receivers. Dave provided two and a half months of in-field support, including a one month reconnaissance trip for the continuous stations and six weeks to conduct the campaign and provide additional support to the continuous stations. He spent an additional three months providing planning, technical and logistics support from the office.

Table 2-7: Support to Turkey and Eastern Mediterranean Projects.

During the data collection period, Dave finished the installation of permanent stations in Yerevan, Armenia and Helwan, Egypt[7] and conducted initial reconnaissance for sites in Istanbul, Turkey and Crimea, Ukraine. This work was jointly funded through the NASA DOSE program and NSF-EAR. During this trip, campaign data collection and permanent station operations training occurred in Egypt and permanent station operations training occurred in Armenia. While the investigator negotiated for long-term support to the permanent stations, Dave negotiated support for the campaigns.

Field work in this part of the world includes the challenge of functioning within a decayed infrastructure and with political uncertainty. For example, Dave had driven to Yerevan, Armenia from Tbilisi, Georgia to finish installing the continuous station there and to pick up the equipment from the campaign. He had been in Yerevan twice before, once for reconnaissance when he installed some station infrastructure and the second time at the beginning of the survey to repair a Turborogue receiver and train observers. There was no lodging in Yerevan, so Dave was staying at the in-country collaborator's research lab, which was across town from the GPS station. These rooms, while private, had no electricity. Near the end of his stay, Dave was awakened in a half dreamy state due to a rumbling outside his window, which was occurring at a near-30 second period. Muttering to himself, "that sounds like tanks", he got out of bed, stubbing his toe which thoroughly woke him up so he remembered where he was. He looked out the window and could barely make out the outline of a column of tanks as they drove down the street past his window toward the center of town. Dave grabbed his shoes and ran to the caretaker's room. The caretaker assured him not to worry, that there was simply a parade the next day. But as Dave returned to bed, he thought about how the tanks looked, lights off and turrets swinging. So he quickly got out of bed and convinced his driver to leave at that very moment for the safety of Georgia. By the time they returned to Tbilisi, TV Moscow reported that riots had broken out in central Yerevan. Regardless of these events, the continuous station equipment was successfully installed and, even though the telephones were cut off, email continued between the lab and Georgia. Dave stayed in contact with his collaborators throughout the project and the equipment made it safely back through the mail.

The results of poor roads or communications can also result in interesting problems in the field. Dave trained several operators for the campaign in Georgia. The work went as expected but on one occasion two operators called from the Caucasus Mountains reporting that the road was washed out two miles from the site. In addition, they were concerned that the batteries were not being charged by the solar panels as the sun had not been out for several days. Dave instructed them to put the batteries in the car and charge them daily. Dave fully expected them to negotiate with a local farmer to haul the batteries to and from the site to the car. Instead of using the farmer's horse to ferry the batteries down to the car at the washout in the road, however, the operators paid a local farmer to tow the truck to the site with his six oxen. Realizing this was his best chance in a long time to make some extra money, the farmer was now "in the drivers seat" and requesting a high price to tow the truck back to the road. Dave had to negotiate with the farmer for services at a more reasonable rate.

[5] With the advent of NAFTA universities are now required to pay import duties on research equipment.

[6] The was due to Mexico's attempt to curb "La Mordida" or a system of paying officials for service.

[7] These stations will become IGS stations when fully operational.

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