Volcano/Tectonic Seismology

Members

-Michael Carr, United States

-Gustavo A. Chinga, Guatemala

-Mauricio Ciudad Real, El Salvador

-Gustavo Fuente Alba, Chile

-Federico Güendel, Costa Rica

-Steve Jordi, Switzerland

-Héctor Monzón, Guatemala

-Leonel Morales, Guatemala

-Wilfred Strauch, Nicaragua

-Fredy Vargas, Guatemala

The working team believes that there are two important aspects to be evaluated, according to the framework given for the Santa María/Santiaguito volcanic complex. These aspects are:

1) The present state of the seismologic surveillance of the complex:

Personnel in charge of maintenance of the seismographic network in Guatemala indicate that the station which has been maintaining surveillance on has ceased to function because of problems of interference. The origin of these problems is not yet known. This station fulfills another purpose which is to survey seismicity of the Western Region of Guatemala where stations have ceased to operate as well, due to lack of resources for proper maintenance (per diem and transportation). At present, there is is only one portable seismograph located in the Santiaguito observatory.

2) Necessary recommendations to guarantee an appropriate level of surveillance:

The minimum necessity to be fulfilled is the installation of a seismographic network in surrounding areas of the volcanic complex (10 or 15 kilometers) with a station near the crater and additional four distributed nearby. Three of these, including the one near the crater, must at least have a horizontal component. In total we are speaking here of a network with eight channels for seismographic register. This would allow for not only a coverage of the activity produced by the volcano but also for the activity which is tectonically generated. This will allow coverage of a region (i.e.. Western Guatemala) which at the present moment lacks any whatsoever.

We recommend that all signals be sent to the observatory and that a vertical component (the one located near the crater) be sent to INSIVUMEH.

Required Equipment Costs

Five vertical stations $35,500

Three horizontal components $12,300

TOTAL (FBO) $47,800

Objectives

1) Monitor the seismicity of the complex.

2) Help with tectonic seismic surveillance by supporting coverage of national seismographic network for the western part of Guatemala.

Methodology

Daily follow-up of registered activities by complex network, separating that activity which occurs mainly within the network from that which proceeds from the signals emanating from the

complex.

Recommendations

1) Locate the site for seismographic register within the facilities of INSIVUMEH in Quezaltenango.

2) Maintain actual site for surveillance of Santiaguito cone by allocating for such a purpose a portable seismograph (......Solar Panel). Maintain radio communication between both sites.

3) Installation of seismographic network of five stations, three of which will have at least a horizontal component for a total of eight channels. One of these stations should be installed as close as possible to the active crater and the other four within a radius of 10-15 km.

4) Installation of station at register center of intermediate periods (5 seconds).

5) Installation of RSAM system in order to establish a methodology for forecasting of eruptions.

6) Obtain infrastructural support in order to guarantee operations of register center (i.e. small electric plant, LKW, solar panel and batteries).

7) Seek training for personnel of observatory or register center.

8) Require that INSIVUMEH provide matching funds, such as operational and maintenance costs, per diem, vehicles, and personnel salaries.