WP 5.4 Reevaluation of the historical earthquakes in light of the new observations

Start date or starting event:

M12

Lead contractor:

IMOR

Participants:

IMOR, UI

1

Objectives:

The aim of the project is to reevaluate magnitudes, locations and possible fault size for historical events in the South Iceland  seismic zone back to 1700.

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Inputs:

Estimation of damages caused by historical  earthquakes and original documents. Available information about faults related to known historical earthquakes. Surface ruptures and other surface effects caused by the 2000 earthquakes. Questionnaires distributed after the earthquakes on June 17 and 21, 2000. Acceleration (WP 5.3).  Detailed dynamic modelling of the year 2000 earthquakes emerging from other workpackages. Earlier evaluations of the intensities/magnitudes and a database of the historical earthquakes.

Methodology / work description:

Previous estimates of magnitudes and locations of historical events are based on the area of damage zone (defined where at least half of all houses collapsed), the Icelandic formula for attenuation of intensities and the instrumentally observed magnitude (Ms=7.0) of an earthquake in the SISZ 1912. For the recent events we have detailed information about the earthquakes, exact locations, fault geometry and slip.

The effects of the earthquakes (surface faulting and intensities ) are also far better known than for the historical events and now we have in addition acceleration records. Some historical documents will be reanalyzed for estimating intensities. A comparison of  detailed information from the 2000 earthquakes with incomplete data from the historical events gives the possibility to revaluate magnitudes, location and fault size of the historical events and thus make improved hazard assessment possible.

3

Deliverables including cost of deliverable as percentage of total cost of the proposed project:

4

Milestones: Delivery of the above items at the date indicated.