S23A-01
The GEOSCOPE Program: state of the art in 2007
The GEOSCOPE program was launched in 1982 by the National Institute of Sciences of Universe (INSU), a
department of the French National Center of Scientific Research (CNRS), following the initiative of the Institute of
Physics of the Earth of Paris (IPGP). The purpose was the installation of about 25 stations well distributed
worldwide (in particular in the southern hemisphere), in the standard configuration defined by the FDSN (very
broad-band 24 bit, continuous recording at 20sps).
At present, the GEOSCOPE program is operating 28 digital 3-component very- broadband stations. In terms of
site locations, the aim of the GEOSCOPE program is almost fulfilled. Our purpose is to maintain the stations at
original sites (Indian Ocean, Africa) and to fill some geographical gaps at high latitudes in the southern and
northern hemisphere. In particular, at high latitudes in Russia, we plan to install a new station VOR (Vorkuta) and
to move the station SEY (Seimchan) to a new location in northern Kamchatka.
We are also working on improving data quality and transmission. Historically, GEOSCOPE did not operate real-
time data. Continuous data from most of stations arrive with significant delays and records from large events are
teletransmitted from some stations (by phone RTC line or through internet) and are made available within one
day. To improve this situation, we are replacing the old Streckeisen digitizers with new Quanterra data loggers,
essentially Q330-HR ones. Presently data from 13 stations are made available at the IPGP Geoscope Data
Center in near real-time, with a delay depending on the station:
1- ATD (Arta, Djibouti), a joint CTBTO/CERD/G station
2- CAN (Canberra, Australia), a joint ANU/G station
3- DZM (Dzumac, New Caledonia, a joint DASE/CTBTO/G station
4- ECH (Echery, France)
5- FDF (Fort de France, French West Indies)
6- KIP (Kipapa, Hawai), a joint IRIS/USGS/G station
7- PAF (Port aux Français, Kerguelen Island)
8- RER (Riviere de l'Est , La Reunion)
9- SSB (Saint Sauveur-Badole, France)
10- SPB (Sao Paulo, Brazil)
11- TAM (Tamanrasset, Algeria)
12- TAOE Marquesas Islands, a joint DASE/G station
13- TRIS Tristan Da Cunha, a joint IRIS/USGS/G station
Our challenge is to link the maximum number of stations to our Data Center for getting data in real time. To reach
this objective in a few years, we plan to upgrade more than 2 stations every year, our priority in 2007 is the
upgrade of stations PEL and COYC in Chile.
For the last ten years we have been progressively installing en environmental sensors (microbaromètres,
thermometers), transforming all our stations in multiparameter observatories.
We also are participating to the national efforts for the creation of a Tsunami Warning Center at La Réunion
Island in the frame of the CNATOI project (Centre National d'Alerte aux Tsunamis dans l'Océan Indien). That
project includes the installation of two new stations in 2007, one at Rodrigues Island (Mauritius) and one at Fort-
Dauphin (NAM station, Madagascar).
Daily automatic procedures allow to compute the noise level plots of each component, for each station in near
real-time, in order to detect any anomalous behaviour of the station and to follow the station status.
http:www.ipgp.jussieu.fr/geoscope
S23A-02
Measuring the Performance of the Global Seismographic Network
The Global Seismographic Network (GSN) is a 144-station, permanent network of state-of-the-art seismological and geophysical sensors and has been constructed and maintained through collaboration between IRIS, USGS, the University of California San Diego, and NSF in coordination with the scientific community. Distributed across all continents and on islands throughout the world's oceans, the network offers a core infrastructure of site agreements, power, and telemetry systems for hosting both seismological instrumentation as well as other geophysical sensors, including GPS, gravimeters, magnetometers, barographs, and meteorological instrumentation. Real- time telemetry is available at more than 93% of GSN sites through a diverse combination of satellite links, hubs, leased-lines, radios, and Internet. GSN cooperates with over 100 host organizations and seismic networks in 64 countries. Approximately 126 of these sites are operated and maintained through the USGS Albuquerque Seismological Laboratory and the IRIS/IDA group at the University of California at San Diego, while the remaining sites are operated by other agencies and hosts. Designed initially as a scientific network during a time when global telemetry was quite limited, original design goals of the network always included real- time telemetry. With the rapid advancement of global telecommunications, the GSN has become a valuable contributor to the global seismic monitoring community and now plays a critical role in earthquake and tsunami hazard real-time warning systems as well as a valuable part of the International Monitoring System of the Comprehensive Nuclear-Test-Band Treaty Organization. As such, the mission of the GSN has expanded to include these very valuable monitoring functions. As the role of the GSN expands, it becomes more important to quantify performance of the network so that the monitoring communities may better understand the reliability of this network and plan their own missions around its use. With the complexity of the operations and maintenance relationships, heterogeneity of the telemetry links and distribution of the network operations, the establishment of standardized performance metrics for this network is a challenge. In this work, we present several different performance measurement techniques that look at data availability, quality, latency and some long-term changes in these metrics in an attempt to assess the performance and value of the GSN in a quantitative sense. Estimates of strengths and weaknesses in the GSN based on these metrics will be made in an attempt to better utilize the available funds the network has for operations and prioritize the use of these funds to meet the needs of the GSN users community.
S23A-03
Web-based tools for real-time assessment of Earthscope's Transportable Array state-of- health: integration of the Antelope Real Time System, RRDtool, AJAX and PHP
Over the past three years the Array Network Facility (ANF) has developed a robust, extensible web-based toolkit for monitoring the state-of-health of Earthscope's Transportable Array. The tools are constructed within a framework of the Antelope Real Time System (ARTS) and the Antelope interface to the PHP Hypertext Processor (PHP), an inline scripting language. Exporting data from Datascope databases and Object Ring Buffer (ORB) packets into XML allows comprehensive client-side interaction via Asynchronous Javascript And XML (AJAX) calls. Navigating and displaying the resultant XML Document Object Model (DOM) trees are done using eXtensible Stylesheet Language Transformation (XSLT) and PHP's built-in DOM classes. Tools include regional and individual station and event maps, state-of-health statistics, waveform plots, and datalogger monitoring. Combined with real-time graphing of state-of-health parameters from status ORB packets using Round Robin Database Tool (RRDtool), this toolkit allows analysts, station engineers, scientists, and the general public to view, assess, interact with, and download data collected from the 250+ stations in the Transportable Array seismic network. Tools are available at the Array Network Facility website, http:anf.ucsd.edu.
S23A-04
Utah's Regional/Urban ANSS Seismic Network---Strategies and Tools for Quality Performance
The University of Utah's regional/urban seismic network (224 stations recorded: 39 broadband, 87 strong-motion, 98 short-period) has become a model for locally implementing the Advanced National Seismic System (ANSS) because of successes in integrating weak- and strong-motion recording and in developing an effective real-time earthquake information system. Early achievements included implementing ShakeMap, ShakeCast, point-to- multipoint digital telemetry, and an Earthworm Oracle database, as well as in-situ calibration of all broadband and strong-motion stations and submission of all data and metadata into the IRIS DMC. Regarding quality performance, our experience as a medium-size regional network affirms the fundamental importance of basics such as the following: for data acquisition, deliberate attention to high-quality field installations, signal quality, and computer operations; for operational efficiency, a consistent focus on professional project management and human resources; and for customer service, healthy partnerships---including constant interactions with emergency managers, engineers, public policy-makers, and other stakeholders as part of an effective state earthquake program. (Operational cost efficiencies almost invariably involve trade-offs between personnel costs and the quality of hardware and software.) Software tools that we currently rely on for quality performance include those developed by UUSS (e.g., SAC and shell scripts for estimating local magnitudes) and software developed by other organizations such as: USGS (Earthworm), University of Washington (interactive analysis software), ISTI (SeisNetWatch), and IRIS (PDCC, BUD tools). Although there are many pieces, there is little integration. One of the main challenges we face is the availability of a complete and coherent set of tools for automatic and post-processing to assist in achieving the goals/requirements set forth by ANSS. Taking our own network---and ANSS---to the next level will require standardized, well-designed, and supported software. Other advances in seismic network performance will come from diversified instrumentation. We have recently shown the utility of incorporating strong-motion data (even from soil sites) into the routine analysis of local seismicity, and have also collocated an acoustic array with a broadband seismic station (in collaboration with Southern Methodist University). For the latter experiment, the purpose of collocated seismic and infrasound sensors is to (1) further an understanding of the physics associated with the generation and the propagation of seismic and low-frequency acoustic energy from shallow sources and (2) explore the potential for blast discrimination and improved source location using seismic and infrasonic data in a synergetic way.
S23A-05
Telemetry Arrays, Autonomous Stations, and Permanent Networks
The advent of the IRIS PASSCAL program has created many opportunities for seismologists to develop and deploy active and passive field experiments. Many of these experiments are either collocated with existing infrastructure such as regional, national, or global network stations. Some experiments benefit from the implementation of the PASSCAL wireless telemetry capability to send data in near real-time. In other cases, PASSCAL instrumentation is deployed in conjunction with Ocean Bottom Seismometers (OBS). In each of these cases, the best possible science resulted from combining all possible datasets together. We will demonstrate problems and solutions used in various experiments to build the best possible data and metadata from disparate sources. We will use the BOLIVAR passive seismic experiment as a case study, which included data from three different systems, PASSCAL Q330 dataloggers, UCSD OBSIP OBSs, and the Funvisis Nanometrics real-time network. We will also examine the appropriateness and the trade-offs for the use of real-time telemetry in temporary experiments include station uptime and network average uptime based on ten temporary deployments of the PASSCAL telemetry systems and the next generation USArray TA and FA systems.
S23A-06
The Budget Guide to Seismic Network Management
Regardless of their size, there are certain tasks that all seismic networks must perform, including data collection
and processing, earthquake location, information dissemination, and quality control. Small seismic networks are
unlikely to possess the resources -- manpower and money -- required to do much in-house development.
Fortunately, there are a lot of free or inexpensive software solutions available that are able to perform many of the
required tasks. Often the available solutions are all-in-one turnkey packages designed and developed for much
larger seismic networks, and the cost of adapting them to a smaller network must be weighed against the ease
with which other, non-seismic software can be adapted to the same task.
We describe here the software and hardware choices we have made for the New England Seismic Network
(NESN), a sparse regional seismic network responsible for monitoring and reporting all seismicity within the
New England region in the northeastern U.S. We have chosen to use a cost-effective approach to monitoring
using free, off-the-shelf solutions where available (e.g., Earthworm, HYP2000) and modifying freeware solutions
when it is easier than trying to adapt a large, complicated package. We have selected for use software that is:
free, likely to receive continued support from the seismic or, preferably, larger internet community, and modular.
Modularity is key to our design because it ensures that if one component of our processing system becomes
obsolete, we can insert a suitable replacement with few modifications to the other modules. Our automated event
detection, identification and location system is based on a wavelet transform analysis of station data that arrive
continuously via TCP/IP transmission over the internet. Our system for interactive analyst review of seismic
events and remote system monitoring utilizes a combination of Earthworm modules, Perl cgi-bin scripts, Java,
and native Unix commands and can now be carried out via internet browser from anywhere in the world. With our
current communication and processing system we are able to achieve a monitoring threshold of about M2.0 for
most New England, in spite of high cultural noise and sparse station distribution, and maintain an extremely high
rate of data recovery, for minimal cost.
http:quake.bc.edu:8000
S23A-07
Enhancement of monitoring for local and regional earthquakes using array techniques and calibration at BURAR (northern Romania) station
Bucovina array (BURAR) is a high-quality monitoring system located in the northern part of Romania, in South- Eastern Carpathians, installed in 2002 and operated in cooperation with Air Force Technical Applications Center - Florida (USA). The system consists of 10 stations (9 short-period and 1 broadband) roughly circularly distributed with 5 km aperture. The BURAR location in a complex seismotectonic area with strong lateral variations, makes imperative the proper calibration of the recording system in order to enhance its capability to identify and localize seismic events. Thus, of highest significance is the strong lateral inhomogeneity of the lithosphere in connection with the sharp concentration of intermediate-depth earthquakes at the SE Carpathians arc bend, in Vrancea region. A significant intermediate-depth seismicity is generated here in an extremely confined focal volume. Understanding the characteristic structural features related to the main seismotectonic and magmatic processes in this area is essential in correctly discerning seismic phases and explaining the observed deviations of their travel times from those expected for global average structural models. Azimuth bias information and distance dependent correction factors in azimuth and slowness are investigated on the basis of local and regional events observed within 2000 km radius and interpreted in correlation with the regional modeling features. The new parametrization and calibration are applied to enhance signal detection and seismic phase identification in case of local and regional earthquakes recorded by BURAR array. The ability of the BURAR array to detect, localize and evaluate magnitude of local and regional events as station alone is also investigated.
S23A-08
High-Performance Tools: Nevada's Experiences Growing Network Capability
Like most regional seismic networks, the Nevada Seismic Network relies on a combination of software components to perform its mission. Core components for automatic network operation are from Antelope, a real- time environmental monitoring software system from Boulder Real-Time Technologies (BRTT). We configured the detector for multiple filtering bands, generally to distinguish local, regional, and teleseismic phases. The associator can use all or a subset of detections for each location grid. Presently we use detailed grids in the Reno-Carson City, Las Vegas, and Yucca Mountain areas, a large regional grid and a teleseismic grid, with a configurable order of precedence among solutions. Incorporating USArray stations into the network was straight- forward. Locations for local events are available in 30-60 seconds, and relocations are computed every 20 seconds. Testing indicates that relocations could be computed every few seconds or less if desired on a modest Sun server. Successive locations may be kept in the database, or criteria applied to select a single preferred location. New code developed by BRTT partially in response to an NSL request automatically launches a gradient-based relocator to refine locations and depths. Locations are forwarded to QDDS and other notification mechanisms. We also use Antelope tools for earthquake picking and analysis and for database viewing and maintenance. We have found the programming interfaces supplied with Antelope instrumental as we work toward ANSS system performance requirements. For example, the Perl language interface to the real-time Object Ring Buffer (ORB) was used to reduce the time to produce ShakeMaps to the present value of ~3 minutes. Hypoinverse was incorporated into a real-time system with Perl ORB access tools. Using the Antelope PHP interface, we now have off-site review capabilities for events and ShakeMaps from hand-held internet devices. PHP and Perl tools were used to develop a remote capability, now nearly operational, by which technicians in the field can trigger a calibration pulse and signal to pulse analysis software at UNR. Station status similar to the Array Network Facility at UCSD has been implemented in PHP. Network analysts are using Antelope Matlab access methods to estimate focal mechanisms selectably from first motions and/or P/S amplitude ratios. The db2xml Antelope extension allows us to export any database table or view directly to XML. This capability will underlie XML data and parametric information exchange. Because ORB and database access tools are available in high-level languages all of the above could be done without resort to compilers or compiled languages. This is perhaps most important for improving network performance in the long run because more of the staff can contribute to network development.
S23A-09
Monitoring and Reporting Tools of the International Data Centre and International Monitoring System
The Comprehensive Test-Ban Treaty (CTBT) which prohibits all nuclear explosions was opened for signature in 1996. Since then, the Preparatory Commission for the CTBT Organization has been working towards the establishment of a global verification regime to monitor compliance with the ban on nuclear testing. The International Monitoring System (IMS) comprises facilities for seismic, hydroacoustic, infrasound and radionuclide monitoring, and the means of communication. This system is supported by the International Data Centre (IDC), which provides objective products and services necessary for effective global monitoring. Upon completion of the IMS, 321 stations will be contributing to both near real-time and reviewed data products. Currently there are 194 facilities in IDC operations. This number is expected to increase by about 40% over the next few years, necessitating methods and tools to effectively handle the expansion. The requirements of high data availability as well as operational transparency are fundamental principals of IMS network operations, therefore, a suite of tools for monitoring and reporting have been developed. These include applications for monitoring Global Communication Infrastructure (GCI) links, detecting outages in continuous and segmented data, monitoring the status of data processing and forwarding to member states, and for systematic electronic communication and problem ticketing. The operation of the IMS network requires the help of local specialists whose cooperation is in some cases ensured by contracts or other agreements. The PTS (Provisional Technical Secretariat) strives to make the monitoring of the IMS as standardized and efficient as possible, and has therefore created the Operations Centre in which the use of most the tools are centralized. Recently the tasks of operations across all technologies, including the GCI, have been centralized within a single section of the organization. To harmonize the operations, an ongoing State of Health monitoring project will provide an integrated view of network, station and GCI performance and will provide system metrics. Comprehensive procedures will be developed to utilize this tool. However, as the IMS network expands, easier access to more information will cause additional challenges, mainly with human resources, to analyze and manage these metrics.
S23A-10
The Global Communication Infrastructure of the International Monitoring System
The Global Communications Infrastructure (GCI) employs 6 satellites in various frequency bands distributed around the globe. Communications with the PTS (Provisional Technical Secretariat) in Vienna, Austria are achieved through VSAT technologies, international leased data circuits and Virtual Private Network (VPN) connections over the Internet. To date, 210 independent VSAT circuits have been connected to Vienna as well as special circuits connecting to the Antarctic and to independent sub-networks. Data volumes from all technologies currently reach 8 Gigabytes per day. The first level of support and a 24/7 help desk remains with the GCI contractor, but performance is monitored actively by the PTS/GCI operations team. GCI operations are being progressively introduced into the PTS operations centre. An Operations centre fully integrated with the GCI segment of the IMS network will ensure a more focused response to incidents and will maximize the availability of the IMS network. Existing trouble tickets systems are being merged to ensure the commission manages GCI incidents in the context of the IMS as a whole. A focus on a single source of data for GCI network performance has enabled reporting systems to be developed which allow for improved and automated reports. The contracted availability for each individual virtual circuit is 99.5% and this performance is regularly reviewed on a monthly basis
S23A-11
Advanced ocean floor network for earthquakes and tsunamis around the Nankai Trough in southwestern Japan
The Nankai Trough is well known as the mega thrust earthquake with an interval of 100-150years. In this area, there are three seismogenic zones such as the Nankai, Tonankai and Tokai seismogenic zone. Therefore, in many researches focusing on the mega-thrust earthquakes around the Nankai trough, the structural researches using refractions and reflections seismic has succeeded to image the key structures to understand recurrences of mega thrust earthquakes around the Nankai Trough. Moreover, results of earthquake recurrence cycle simulation show that the first ruptures seems to occurred around the Tonankai earthquake rupture zone in each recurrence cycle, and the clear segment boundary between the Tonankai and Nankai earthquake rupture zones off the Kii peninsula was analyzed using tsunami data. The 1944 Tonankai and the 1946 Nankai earthquakes, each hypocenter was located off the Kii peninsula. So, the imaged irregular structures such as a key structure at the segment boundary between the Tonankai and Nankai earthquake rupture zone seems to act as the controller of the Tonankai-Nankai mega-thrust earthquake recurrence system. By the advanced simulation study of recurrence cycles of mega-thrust earthquakes around the Nankai Trough, these irregular structures seem to act as a controller of recurrence cycle and pattern of mega- thrust earthquakes in the Nankai Trough. Based on these researches, we proposed and have been starting to deploy the dense ocean floor observatory network system equipped with multi-kinds of sensors such as seismometers, pressure gauges etc., focusing on the understanding of crustal activities off Kii peninsula including the Tonankai/Nankai earthquake rupture zones. The new project of MEXT as the kind of Japanese government is starting from FY2006. This observatory system a will be the one of most advanced scientific tools to understand the mega thrust earthquakes around the Nankai trough. This advanced dense ocean floor observatory network system has useful functions and purposes as follows, 1) Redundancy, Extension and advanced maintenance system using the looped cable system, junction boxes and the ROV/AUV etc. 2) Speedy evaluation and notification for earthquakes and tsunamis Especially, the evaluation and notification for tsunami will be improved remarkably using dense ocean floor observatories. 3) Provide observed data such as ocean floor deformation derived from pressure gauges to improve the simulation and modeling researches about the mega-thrust earthquakes 4) Understanding of the interaction between the crust and upper mantle around subduction zone. In this paper, we will explain the advanced dense ocean floor observatory network system in detail and emphasize the purpose and importance of this system.
S23A-12
The Kyrgyz Seismic Network (KNET)
The Kyrgyz Digital Seismic Network (KNET) is a regional continuous telemetric network of very broadband
seismic data. KNET was installed in 1991. The telemetry system was upgraded in 1998. The seismograms are
transmitted in near real time. KNET is located along part of the boundary between the northern Tien Shan
Mountains and the Kazakh platform. Several major tectonic features are spanned by the network including a
series of thrust faults in the Tien Shan, the Chu Valley, and the NW-SE trending ridges north of Bishkek. This
network is designed to monitor regional seismic activity at the magnitude 3.5+ level as well as to provide high
quality data for research projects in regional and global broadband seismology. The Kyrgyz seismic network array
consists of 10 stations - 3 of them with more than 3600 m altitude, 2 mountain repeaters, 1 intermediate data
base and 2 data centers. One of data centers is a remote source for IRIS data base. KNET is operated by
International Research Center - Geodynamic Proving Ground in Bishkek (IGRC) with the participation of Research
Station of the Russian Academy of Sciences (RS RAS) and Kyrgyz Institute of Seismology (KIS). The network
consists of Streckeisen STS-2 sensors with 24-bit PASSCAL data loggers. All continuous real-time data are
accessible through the IRIS DMC in Seattle with over 95% data availability, which compares favorably to the best
networks currently operating worldwide. National institutes of seismology in Kyrgyzstan and Kazakhstan, National
Nuclear Centre of Kazakhstan, RS RAS, divisions of the ministries on extreme situations and the institutes of the
Russian Academy of Sciences use KNET data for estimating seismic hazards and to study deep-seated structure
of researched territory. KNET data is used by National Nuclear Centre of Republic of Kazakhstan, which together
with LAMONT laboratory (USA) carries out verification researches and monitoring of nuclear detonations in China,
India and Pakistan. The uniform digital Catalogue of Central Asia data which will include Kyrgyzstan, Kazakhstan,
Uzbekistan and KNET seismic networks data is being developed. Chinese scientists have expressed interest in
usage of KNET data, and also in association of a digital network located in the Tarim platform and KNET territory.
http:eqinfo.ucsd.edu/deployments/knet.php
S23A-13
The Texcoco Seismic Array: Analysis of the Seismic Movement in the Deep Sediments of Mexico Basin.
The seismic movement in the Lake Zone of the Mexico Basin is characterized by long durations and late energy arrivals; many efforts have been made to find the origin of these late waves. In 1997 the Texcoco Seismic Array (TXC) was installed in the former Lake of Texcoco, in the northeastern part of Mexico Basin. It is a natural reserve formed by the same lacustrine clays of the Lake Zone in Mexico City, however we consider TXC as a virgin site as there are no buildings near, and there is almost no human activity. We analyzed 7 earthquakes recorded at TXC in two instrumental arrays, to identify late energy arrivals near the fundamental period and we also analyzed these pulses with F-K method to estimate the phase velocity and its origin.