Intrinsic Materials Technology for Flexible Electromagnetic Shields

Locating and discriminating explosions from earthquakes become progressively moredifficult as magnitude decreases. We can no longer rely on teleseismic identificationfor events at about Mw<4.3 and we can expect only a few, perhaps one, digitalstations reporting usable data in regional distance. We need to obtain moreinformation from these regional seismograms than just arrival times and amplituderatios. Here we introduce a new method of estimating source parameters usingas few as one broadband station in conjunction with other available data. We willrefer to these solutions as regional event parameters (REP) to distinguish themfrom other source estimates, such as Ground Truth (GT) location and Centroid MomentTensor (CMT) location. The method employs an adaptive grid-search of matchingthree-component waveform records against synthetics to establish source location anddepth. The basic matching procedure contains a trade-off of source mechanism with location. The better the constraint onmechanism and depth, the better the location. The locations of GT10 and GT25 eventscan also be improved if CMT's and other independent depth estimates are available.We propose a concentrated effort to develop an interactive semi-automated code that can take avariety of data and determine source parameters. To establish proof-of-concept, we willconduct a validation test on the PASSCAL data sets collected in Pakistan and Tibet.We will test our method against the locations of the GT5 and GT10 events. The effective accuracy inlocations produced from the analysis of one broadband station plusfirst arrivals at other stations can be checked against the whole network locations.This code could be used systematically to refine existing locations. Researchers in the various SSSC calibration projects coulduse such a code to help establish the ground truth events in their regions. Moreover, independentlocations by different methodologies could be used to more fully address the trueuncertainties in location.This study will result in a methodology to yield ground truth information for smallmagnitude events using a number of short-period stations for polarity and onset timesof P waves in conjuction with a broadband station. The proposed method is applicable in any tectonic environment providedthat the regional structure is calibrated. Thus, following the Phase-I of this study, it will be possible to apply this methodto reduce ambiguity in the epicentral locations of small magnitude events, which is needed by the OSI requirements.Also, we will be able to extend this method to smaller events with added confindence thus will yielda larger populations of GT events producing a better coverage of the geographic regions of the monitoring interests.