L'Aquila 2009 seismic sequence: integrated dataset of automatic first motion polarities focal mechanisms and RMT with HypoDD high quality relative earthquake locations

This dataset is related to the L'Aquila 2009 seismic sequence that happened in Central Apennines (Italy).

It contains:

• 2782 quality selected focal mechanisms produced with the standard software FPFIT based on automatically determined first motion polarities of automatically detected and analyzed foreshocks and aftershocks recorded from January 2009 to December 2009 (flag fty in the header is MP)
• 475 (out of 627) quality selected focal mechanisms produced with the standard software FPFIT also based on automatically determined first motion polarities but for only 3204 M_L >= 1.9 earthquakes and by using take-off angles calculated within a local 3d tomographic velocity model (Di Stefano et al., 2011) , published and released in Chiaraluce et al., 2011 (flag fty in the header is JG)
• 165 (out of 181) Regional Moment Tensors determined for earthquakes M_L >= 3.0 based on broadband waveform inversion of ground velocities and published by Hermann et al., 2011 (flag fty in the header is HM)
• The hypocenters of the total 3422 earthquakes reported in the present focal solutions dataset have been taken from the very high quality double difference locations of the about 64000 aftershocks reported in Valoroso et al., 2013 and published, as part of the full dataset, on Zenodo. 

The association between the focal solutions and the HypoDD hypocenters has been performed through the direct use of the HypoDD event identifier where possible (the whole MP dataset) and through spatial and temporal earthquakes coordinates matching in all the other case by using the capability of a MySQL database. 

Two files are uploaded, one in plain text with blank separator, the second in plain text with ";" separator and .csv extension.

Here below the header is explained.

OT_Date: date of the origin time in the format YYYY-MM-DD

OT_Time: time of the origin time in the format HH:mm:ss.dcm

lat: hypocenter latitude expressed in degrees 

lon: hypocenter longitude east of Greenwich, expressed in degrees

dep: hypocenter depth expressed in km 

ML: local magnitude (pure number) from Valoroso et al., 2013 (see last column notes also)

id_dd: the hypoDD event identifier, allowing to directly connect to the Valoroso et al., 2013 full dataset

IMPORTANT NOTE about st1 and st2 (below): the focal solutions are presented here based on the convention they where produced or published, so there are two different (but compatible) conventions for the fault plains orientation in the 3d space

st1:

• for fty=HM or JG this is the strike of plane 1 (CMT convention)
• for fty=MP this is the strike of the dip direction of plain 1 (FPFIT convention)

dip1: dip of plane 1

rk1: rake of plane 1

st2:

• for fty=HM or JG this is the strike of plane 2 (CMT convention)
• for fty=MP this is the strike of the dip direction of plain 2 (FPFIT convention)

dip2: dip of plane 2

rk2: rake of plane 2

fty: flag to distinguish the type of solution, CMT=HM or JG, FPFIT=MP

MW: only for HM, this columns reports also MW from Hermann et al., 2011