The Full Picture

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the number and quality of stations in those regions of the

world where station distribution is less than ideal. Some

examples of regions where seismographic coverage is

improving are Latin America, Africa and some parts of Asia.

The federation has given high priority to encouraging and

supporting the installation of stations on the bottom of the

oceans. The Earth, being essentially an oceanic planet, has

large areas where the installation of seismological observ-

ing stations is restricted to islands. Several international

efforts are underway, using cutting edge technology to

install seismographic stations in the various ocean basins.

FDSN and GEOSS: a fruitful interaction

In February 2005, the FDSN subscribed the ten-year imple-

mentation plan of GEO. In this manner, FDSN embraced

the goals of GEO by contributing seismological data of the

highest quality available, which may be distributed openly

for the benefit of society. As mentioned above, the federa-

tion has encouraged for many years the transmission and

distribution of data in real time, another of the main goals

of GEOSS. In fact, FDSN is probably the most developed

and integrated system of in situ observatories now

contributing to the GEOSS effort.

Within GEOSS, the FDSN offers the participation and

representation of a global community of seismographic

network operators in a coordinated and structuredmanner.

Additionally, the federation has contributed routinely to

GEO its expertise in the real-time transmission of data and

in the development of common formats and protocols for

the transmission, archiving, exchange and retrieval of data.

One of the main goals of GEOSS is the production and

distribution of information that allows the future develop-

ment of sustainable communities and societies. One of the

important elements for this is the prevention and reduc-

tion of the loss of lives and property caused by natural

disasters. FDSN provides GEOSS with the global infra-

structure that is crucial to meeting the societal benefit

enunciated by GEO of reducing disaster losses in the realm

of earthquakes and tsunamis.

The experience of the Sumatra and Indian Ocean

tsunami, which claimed over 300,000 lives in 2004,

eloquently illustrates the importance of strengthening and

improving the timely processing and distribution of rele-

vant data to support the efforts of international agencies

and governmental organizations in disaster relief and

prevention. Although the primary mission of the FDSN is

not disaster prevention, it is well aware of the importance

of the data that it produces for these efforts and strives to

maintain a close collaboration with those agencies respon-

sible for these tasks. Thus FDSN has offered its own

resources and its close collaboration and synergy with other

institutions like the US National Earthquake Information

Center, the EuropeanMediterranean Seismological Center

and the Intergovernmental Oceanographic Commission of

UNESCO (IOC), to actively contribute to two of the goals

of the ten-year implementation plan of GEO: the reduc-

tion of losses due to natural disasters and the understanding

of our environment as it may affect human lives and well-

being.

in Japan. In the exchange of data a common format called Standard for

the Exchange of Earthquake Data (SEED) was developed by one of the

working groups of the federation, and its use is strongly recommended.

This format, however, is not compulsory and members of the federa-

tion may transmit their data in a different manner. FDSN has also

developed software, which it also distributes freely, to convert into and

from SEEDmost of the formats used today. Common software developed

by the federation for data mining and retrieval from all data centres is

also freely and openly accessible to users and network operators.

The seismographic networks that contribute data to the federation

can be categorized into two main levels. There are global networks that

install and maintain a large number of seismographic observatories

distributed globally. The Global Seismographic Network (GSN) of IRIS,

GEOFON of Germany, GEOSCOPE of France and Pacific21 of Japan,

are examples of these global networks, and they all operate state-of-the-

art seismological observatories. These networks adhere strictly to the

recommendations of the FDSN of using broadband seismic instrumen-

tation to faithfully record the full spectrum of seismic signals with high

fidelity. The mission of these global networks is mainly scientific and

they all contribute and participate actively in the tsunami warning and

disaster prevention efforts at all levels.

Other seismographic networks that are also part of the FDSN are of

national, regional or local extent. These networks generally do not have

the production of data for scientific research as their main priority.

Instead, they are tasked to monitor seismicity and to contribute to the

evaluation of seismic hazard in their national territories or regions. These

operators are less demanding in the use of broadband seismic instru-

ments and data distribution, and exchange with other users or operators

is often controlled by their available technical and financial resources.

More and more of these operators, however, are now contributing data

to the FDSN data centres both in real time and in archival exchange.

The global exchange of seismic data is measured in tens of terabytes per

year.

The coverage of seismic observatories around the world is unfortu-

nately not homogeneous. The FDSN is collaborating with national and

international agencies and seismological network operators to improve

Geographic distribution of FDSN ‘Backbone’ stations

The FDSN ‘Backbone’ stations’ data are archived at the Data Management

Center of IRIS and distributed in real-time by FDSN members. The different

symbols indicate the different parent networks contributing the data

Annual mean

Source: Incorporated Research Institutions for Seismology (IRIS)

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