24th General Assembly of IUGG and 34th General Assembly of IASPEI

Perugia, Italy 2-13 July 2007

Report to IUGG on IASPEI 2007 Activities

IASPEI Resolutions adopted at the IASPEI Closing Plenary in Perugia (Italy)

Resolution 1: Use of model ak135 for earthquake location

  • RECOGNIZING that the workshops on 'Modernizing ISC location procedures' have demonstrated that the ak135 traveltime tables provide a better fit than the Jeffreys-Bullen (JB) tables to observed seismic phases,


  • RECOMMENDS that the International Seismological Centre replace the JB model by ak135 for the routine location of seismic events.

Resolution 2: Consistent determination & reporting of earthquake source parameters

  • RECOGNIZING the long-term need for a broader set of standardized seismological phase and parameter data in seismological research and practice, especially amplitude, period, magnitude, moment and energy,


  • RECOMMENDS that steps be taken to develop common standards for the reporting of earthquake source parameters for use by national, regional and global data centers.

Resolution 3: Timely reporting to ISC

  • RECOGNIZING that the ISC provides an on-line compilation of parametric data contributed by observatories and data centres, available to all soon after they are contributed,


  • URGES all ISC contributors to report epicentres, magnitudes, phases and focal mechanisms to the ISC as quickly as possible.

Resolution 4: Naming the unit of Seismic Moment after Prof. Kei-iti Aki

  • RECOGNIZING that seismic moment is widely used as a fundamental measure of the size of an earthquake, and

  • RECOGNIZING that Prof. Kei-iti Aki was a pioneer in defining seismic moment and describing practical ways to measure it,


  • RECOMMENDS that 1 Aki (Ak) be defined as 1018 Nm, and further

  • RECOMMENDS that the Aki be recognized as a standard unit of earthquake size.

Resolution 5: Appreciation

  • RECOGNIZING the enormous effort required to organise the General Assembly,


THANKS the IUGG Local Organizing Committee and its Chair Professor Lucio UBERTINI for a memorable meeting in Perugia.