SeisComP User Group Meeting

2010, Potsdam

SeisComP

Moment Tensors

Jan Becker

gempa GmbH

Goal

● (C)MT computation in realtime● More data in → more reliable solution out

● Fast and stable● Cover full magnitude range● Local and global scale● Interactive analysis tools● Full integration into SeisComP

Evolution

2007-2009● first automatic version based on Dreger codes / scripts

● simple data integration instead of deconvolution

● solutions were not convincing

2009-2010● development of interactive analysis tools

● new MT inversion code based on SeisComP framework

● 1-3 components, full waveforms

● algorithm not stable enough

● gained experience with long period data and inversion process

Evolution

2010● integration of Kiwi tools into SeisComP (http://kinherd.org) by

Sebastian Heimann (not yet complete)

● complete rewrite of inversion code

● Gemini PREM Greens function database up to 90 deg distance and 0-700 km depth

● 1-3 components, separation of body- and surface waves

● automatic tool for hypocenter and centroid solutions

● analysis tools need a rewrite due to new algorithm

Hypocenter algorithm

● Time domain● Usage of full responses● Separation of body- and surface waves● Clean data set (SNR, amplitude outliers, ...)● Adaptive depth search● Filtertests● Optimization of solution

Centroid algorithm

● Time domain● Starts from hypocenter solution● Adaptive 4D gridsearch (location, depth & time)

that follows local maxima● Grid size derived from rupture area computed

from relationships by Wells & Coppersmith (1994)

Where are we now?

● Automatic (C)MT tool in testing mode● Processing of results within SeisComP● Dissemination of results to a web page● Promising results in comparison to GlobalCMT

and USGS● No interactive analysis tools again

Future plans

● Analysis tools● W-Phase● Automated tests with global data and reference

solutions from GlobalCMT● Greens function database for other earth

models (e.g. IASP91)● Improve speed (CPU: multithreading, ALG: start

with body waves only)● Automatic detection of periods instead of

testing different predefined periods

Acknowledgment

● John Clinton, ETHZ● Initial support and filter settings

● Sebastian Heimann, Hamburg University● Deconvolution, filtering, decimation, inversion,

science, everything!

● John Ristau, GNS Science● Joachim Saul, German Research Centre for

Geosciences● Greens function database, scientific support and

comments

Thank you

● Questions?

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