IRIS DMC Research Articles

Estimation of Flores Sea Aftershock Rupture Data Based on AI

The earthquake catalog notes that there have been earthquakes with Mw > 7 that hit the Flores area, three of which occurred in the Flores Sea in 1992, 2015, and 2021. Revealed that the seismic activity of Eastern Indonesia is thought to be influenced by the isolated thrust fault segment of the island of Flores and the island of Wetar. The study of the rising fault segment on Flores Island and Wetar Island helps in further understanding the fault behavior, earthquake pattern, and seismic risk in the Flores Sea region. In earthquakes with giant magneto, an aftershock can occur due to the interaction of ground movements. This research analyzes and compares the data from the evaluation of the classification algorithm and the regression algorithm. The initial stages of this research include requesting IRIS DMC Web Service data. The data is then subjected to a cleaning process to obtain the expected feature extraction. The next stage is to perform the clustering process. This stage is carried out to label dependent data by adding new features as data clusters. The following procedure divides the validation value, which consists of training and test data. The estimation results show that the classification algorithm's evaluation value is better than that of the regression algorithm. The evaluation value of several algorithms indicates this, with an accuracy rate between 80% and 100%.

The INSIEME seismic network: a research infrastructure for studying induced seismicity in the High Agri Valley (southern Italy)

Abstract. The High Agri Valley is a tectonically active area in southern Italy characterized by high seismic hazard related to fault systems capable of generating up to M=7 earthquakes (i.e. the 1857 Mw=7 Basilicata earthquake). In addition to the natural seismicity, two different clusters of induced microseismicity were recognized to be caused by industrial operations carried out in the area: (1) the water loading and unloading operations in the Pertusillo artificial reservoir and (2) the wastewater disposal at the Costa Molina 2 injection well. The twofold nature of the recorded seismicity in the High Agri Valley makes it an ideal study area to deepen the understanding of driving processes of both natural and anthropogenic earthquakes and to improve the current methodologies for the discrimination between natural and induced seismic events by collecting high-quality seismic data. Here we present the dataset gathered by the INSIEME seismic network that was installed in the High Agri Valley within the SIR-MIUR research project INSIEME (INduced Seismicity in Italy: Estimation, Monitoring, and sEismic risk mitigation). The seismic network was planned with the aim to study the two induced seismicity clusters and to collect a full range of open-access data to be shared with the whole scientific community. The seismic network is composed of eight stations deployed in an area of 17 km×11 km around the two clusters of induced microearthquakes, and it is equipped with triaxial weak-motion broadband sensors placed at different depths down to 50 m. It allows us to detect induced microearthquakes, local and regional earthquakes, and teleseismic events from continuous data streams transmitted in real time to the CNR-IMAA Data Centre. The network has been registered at the International Federation of Digital Seismograph Networks (FDSN) with code 3F. Data collected until the end of the INSIEME project (23 March 2019) are already released with open-access policy through the FDSN web services and are available from IRIS DMC (https://doi.org/10.7914/SN/3F_2016; Stabile and INSIEME Team, 2016). Data collected after the project will be available with the permanent network code VD (https://doi.org/10.7914/SN/VD, CNR IMAA Consiglio Nazionale delle Ricerche, 2019) as part of the High Agri Valley geophysical Observatory (HAVO), a multi-parametric network managed by the CNR-IMAA research institute.

Digitization of the Carnegie Analog Broadband Instruments Tape Records (1965–1996)

AbstractBetween 1965 and 2003, the Carnegie Institution of Washington’s Department of Terrestrial Magnetism operated a continuous network of nine broadband seismographs with locations in South America, Japan, Iceland, Papua New Guinea, and Washington, D.C. The Carnegie seismographs designed in the 1960s by Selwyn Sacks were among the earliest broadband instruments, sensing between at least 30 s and ∼30 Hz. Given the scarcity of historic seismic data of comparable bandwidth and dynamic range prior to the widespread shift to force-feedback instruments and digital recording around the mid-1980s, this dataset is still of high scientific value today.The Carnegie seismographs recorded data to magnetic tapes meant to be read and analyzed using a custom playback system. Since 1989 these tapes have been stored in a climate-controlled, electromagnetically shielded room, which preserved them in reasonably good condition. However, some tapes now show signs of moisture damage, and reading them is difficult and time consuming by today’s standards, creating a barrier to the use of this dataset. To overcome these issues, we have undertaken an ongoing effort to digitize this dataset with the goal of making it publicly available in Standard for the Exchange of Earthquake Data (SEED) format at the Incorporated Research Institutions for Seismology Data Management Center (IRIS DMC).

Lateral variations in the crustal structure of the Indo–Eurasian collision zone

We thank Michael Ritzwoller and two anonymous reviewers for constructive comments that have helped improve the manuscript. The majority of the seismic data used in this study were downloaded from IRIS DMC. Data for the NGRI stations in India were provided by S. S. Rai, and Zahid Rafi provided the PMD Pakistan data. Kajal Borah provided the ambient noise cross-correlations for the Uttaranchal network. Figures were prepared using Generic Mapping Tools (GMT) software (Wessel and Smith, 1998). We thank Robert Herrmann for making the Computer Programs in Seismology freely available.

Improvements in Data Quality, Integration and Reliability: New Developments at the IRIS DMC

Abstract. With the support of the US National Science Foundation (NSF) and on behalf of the international seismological community, IRIS developed a Data Management Center (DMC; Ahern, 2003) that has for decades acted as a primary resource for seismic networks wishing to make their data broadly available, as well as a significant point of access for researchers and monitoring agencies worldwide that wish to access high quality data for a variety of purposes. Recently IRIS has taken significant new steps to improve the quality of and access to the services of the IRIS DMC. This paper highlights some of the current new efforts being undertaken by IRIS. The primary topics include (1) steps to improve reliability and consistency of access to IRIS data resources, (2) a comprehensive new approach to assessing the quality of seismological and other data, (3) working with international partners to federate seismological data access services, and finally (4) extensions of the federated concept to extend data access to data from other geoscience domains.

ObsPyLoad: A Tool for Fully Automated Retrieval of Seismological Waveform Data

Research Article| May 01, 2013 ObsPyLoad: A Tool for Fully Automated Retrieval of Seismological Waveform Data Chris Scheingraber; Chris Scheingraber aDepartment of Earth and Environmental Sciences, Ludwig‐Maximilians‐Universität München, Theresienstrasse 41, 80333 Munich, Germanychris@scheingraber.nethosseini@geophysik.uni-muenchen.desigloch@geophysik.uni-muenchen.de Search for other works by this author on: GSW Google Scholar Kasra Hosseini; Kasra Hosseini aDepartment of Earth and Environmental Sciences, Ludwig‐Maximilians‐Universität München, Theresienstrasse 41, 80333 Munich, Germanychris@scheingraber.nethosseini@geophysik.uni-muenchen.desigloch@geophysik.uni-muenchen.de Search for other works by this author on: GSW Google Scholar Robert Barsch; Robert Barsch bEGU Executive Office, Luisenstr. 37, 80333 Munich, Germanybarsch@egu.eu Search for other works by this author on: GSW Google Scholar Karin Sigloch Karin Sigloch aDepartment of Earth and Environmental Sciences, Ludwig‐Maximilians‐Universität München, Theresienstrasse 41, 80333 Munich, Germanychris@scheingraber.nethosseini@geophysik.uni-muenchen.desigloch@geophysik.uni-muenchen.de Search for other works by this author on: GSW Google Scholar Author and Article Information Chris Scheingraber aDepartment of Earth and Environmental Sciences, Ludwig‐Maximilians‐Universität München, Theresienstrasse 41, 80333 Munich, Germanychris@scheingraber.nethosseini@geophysik.uni-muenchen.desigloch@geophysik.uni-muenchen.de Kasra Hosseini aDepartment of Earth and Environmental Sciences, Ludwig‐Maximilians‐Universität München, Theresienstrasse 41, 80333 Munich, Germanychris@scheingraber.nethosseini@geophysik.uni-muenchen.desigloch@geophysik.uni-muenchen.de Robert Barsch bEGU Executive Office, Luisenstr. 37, 80333 Munich, Germanybarsch@egu.eu Karin Sigloch aDepartment of Earth and Environmental Sciences, Ludwig‐Maximilians‐Universität München, Theresienstrasse 41, 80333 Munich, Germanychris@scheingraber.nethosseini@geophysik.uni-muenchen.desigloch@geophysik.uni-muenchen.de Publisher: Seismological Society of America First Online: 09 Mar 2017 Online ISSN: 1938-2057 Print ISSN: 0895-0695 © 2013 by the Seismological Society of America Seismological Research Letters (2013) 84 (3): 525–531. https://doi.org/10.1785/0220120103 Article history First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Chris Scheingraber, Kasra Hosseini, Robert Barsch, Karin Sigloch; ObsPyLoad: A Tool for Fully Automated Retrieval of Seismological Waveform Data. Seismological Research Letters 2013;; 84 (3): 525–531. doi: https://doi.org/10.1785/0220120103 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search We confront the data avalanche: the amount of waveform data available from seismological data centers has been growing enormously over the past few years. This is a highly welcome development from a scientific point of view, but the time and effort spent on identification, retrieval, and quality control of subsets of these data may quickly exceed tolerable limits for an individual researcher. Data from different data centers may not be available through the same interfaces or may arrive in different formats, which have tended to change over time. This often results in time‐consuming homogenization efforts. The situation has improved in... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

FuncLab: A MATLAB Interactive Toolbox for Handling Receiver Function Datasets

Receiver functions have become a widely used tool to study the seismic velocity structure beneath a single station by imaging impedance boundaries where mode conversions from P to S waves occur. In recent years, the community has seen an increase in the amount of broadband seismic data available through systems such as the IRIS Data Management Center (IRIS DMC), requiring new approaches to managing and handling large datasets in computationally efficient ways. Many receiver function studies have focused on tectonic and geodynamic questions on regional scales of a few hundred square kilometers ( e.g. , Zandt et al. 1995; Sheehan et al. 1995; Dueker and Sheehan 1997). These studies typically have utilized data from temporary networks operating on time scales of a few months to a few years. Others have concentrated on global trends, using data from increasing numbers stations that have operated for years or decades ( e.g. , Andrews and Deuss 2008; Lawrence and Shearer 2006; Tauzin et al. 2008). Over the last several years, the seismological community has seen a rapid increase in the number of deployed passive broadband seismic stations and a resulting increase in data available for receiver function analysis. Large initiatives such as EarthScope’s USArray Transportable Array enable immediate open access to data and have provided the community with an order of magnitude more data than in the previous three decades (Figure 1) based on smaller regional temporary studies using data from IRIS PASSCAL-style field experiments ( e.g. , Suckale et al. 2009; Wilson et al. 2005). While the computation of receiver functions has been well studied and is a relatively straightforward and rapid process, an efficient method to analyze and further evaluate very large receiver function datasets is not widely available. In this paper, we present an efficient workflow and …

Rupture imaging of the Mw 7.9 12 May 2008 Wenchuan earthquake from back projection of teleseismic P waves

The Mw 7.9 Wenchuan earthquake of 12 May 2008 was the most destructive Chinese earthquake since the 1976 Tangshan event. Tens of thousands of people were killed, hundreds of thousands were injured, and millions were left homeless. Here we infer the detailed rupture process of the Wenchuan earthquake by back‐projecting teleseismic P energy from several arrays of seismometers. This technique has only recently become feasible and is potentially faster than traditional finite‐fault inversion of teleseismic body waves; therefore, it may reduce the notification time to emergency response agencies. Using the IRIS DMC, we collected 255 vertical component broadband P waves at 30–95° from the epicenter. We found that at periods of 5 s and greater, nearly all of these P waves were coherent enough to be used in a global array. We applied a simple down‐sampling heuristic to define a global subarray of 70 stations that reduced the asymmetry and sidelobes of the array response function (ARF). We also considered three regional subarrays of seismometers in Alaska, Australia, and Europe that had apertures less than 30° and P waves that were coherent to periods as short as 1 s. Individual ARFs for these subarrays were skewed toward the subarrays; however, the linear sum of the regional subarray beams at 1 s produced a symmetric ARF, similar to that of the groomed global subarray at 5 s. For both configurations we obtained the same rupture direction, rupture length, and rupture time. We found that the Wenchuan earthquake had three distinct pulses of high beam power at 0, 23, and 57 s after the origin time, with the pulse at 23 s being highest, and that it ruptured unilaterally to the northeast for about 300 km and 110 s, with an average speed of 2.8 km/s. It is possible that similar results can be determined for future large dip‐slip earthquakes within 20–30 min of the origin time using relatively sparse global networks of seismometers such as those the USGS uses to locate earthquakes in near–real time.

Shear and compressional velocity models of the mantle from cluster analysis of long-period waveforms

SUMMARY We present a new technique for the efficient measurement of the traveltimes of long period body wave phases. The technique is based on the fact that all arrivals of a particular seismic phase are remarkably similar in shape for a single event. This allows the application of cross-correlation techniques that are usually used in a regional context to measure precise global differential times. The analysis is enhanced by the inclusion of a clustering algorithm that automatically clusters waveforms by their degree of similarity. This allows the algorithm to discriminate against unusual or distorted waveforms and makes for an extremely efficient measurement technique. This technique can be applied to any seismic phase that is observed over a reasonably large distance range. Here, we present the results of applying the algorithm to the long-period channels of all data archived at the IRIS DMC from 1976 to 2005 for the seismic phases S and P (from 23 ◦ to 100 ◦ ) and SS and PP (from 50 ◦ to 170 ◦ ). The resulting large data sets are inverted along with existing surface wave and updated differential traveltime measurements for new mantle models of S and P velocity. The resolution of the new model is enhanced, particularly, in the mid-mantle where SS and PP turn. We find that slow anomalies in the central Pacific and Africa extend from the core‐mantle boundary to the upper mantle, but their direct connection to surface hotspots is beyond our resolution. Furthermore, we find that fast anomalies that are likely associated with subducting slabs disappear between 1700 and 2500 km, and thus are not continuous features from the upper to lower mantle despite our extensive coverage and high resolution of the mid-mantle.

The structure of the base of the outer core inferred from seismic waves diffracted around the inner core

We systematically searched for seismograms of waves diffracted around the inner core (PKPCdiff) from all the temporary seismic arrays with data currently available at the IRIS DMC, as well as some permanent regional seismic arrays including F‐NET in Japan and GRF in Germany, to assemble the largest high‐quality PKPCdiff database ever created. PKPCdiff waves preferentially sample the base of the outer core and so contain important clues about Earth structure in this region. We measured PKPDF–PKPCdiff differential traveltimes and PKPCdiff/PKPDF amplitude ratios in the distance range of 154°–160° and modeled the observations using grid searches and full wave theory synthetic seismograms. The optimum model found by fitting the differential traveltimes has relatively low velocity at the base of the outer core as in AK135, which is consistent with many previous traveltime studies. However, the optimum model found by fitting the amplitude ratios (PKPCdiff/PKPDF) does not exhibit this feature, and instead is closer to PREM. The discrepancy may be explained by two likely causes. One is that small‐scale topography or roughness on the ICB tends to scatter energy away from PKPCdiff waves by generating trailing coda waves. The other is that there exists a thin layer with relatively low Q at the base of the outer core. This might be expected if there are suspended solid particles at the base of the outer core, as proposed decades ago. Both mechanisms could generate smaller PKPCdiff amplitudes without significantly affecting PKPCdiff traveltimes.

Automated Receiver Function Processing

The aim of this is article is twofold: first to introduce an automated processing system based on SOD (Standing Order far Data , http://www.seis.sc.edu/SOD/) (Owens et al. , 2004), and second to give some initial results and pitfalls from our experience with using this system for automated receiver function calculations. EARS, the EarthScope Automated Receiver Survey, aims to calculate bulk crustal properties for all stations within the continental United States that are available from the IRIS DMC using receiver functions and to distribute these results to interested research and education communities as a “product” of the USArray component of EarthScope. Because of the high level of automation that this requires, a natural extension of this effort is to calculate similar results for all stations in the IRIS DMC. To do this we have employed SOD , a FISSURES/DHI-based software package (Ahern, 2001a, b) that we have developed to do automated data retrieval and processing. We introduce EARS as an example of what we term “receiver reference models” They are standard analysis techniques applied to stations. These are analogous to the Harvard Centroid Moment Tensor solutions (which could be termed source reference models). An RRM need not be a definitive result but rather provides a standard, well known, globally consistent reference. This may be sufficient for many users, just as CMT's are sufficient for many, but may also be a starting point for more in-depth, focused studies. The key features of an RRM are that it be generated from a well known and widely accepted technique, produce results for most or all stations, and provide updated results as new sources of data become available. In addition, it must produce results that are of interest in a form usable by the community. Because automated processing proceeds, by definition, without a large …

The GEOSCOPE program: its data center

The purpose of the GEOSCOPE program was the installation of about 20 stations well distributed worldwide (in particular in the southern hemisphere), in the standard configuration defined by the FDSN (VBB 24 bit, continuous recording at 20 samples/s (sps)). The installation is almost complete. The effort has been focused on the accessibility of data from our Data Center. Data can be obtained either on line through the WWW GEOSCOPE server (http://geoscope.ipgp.jussieu.fr), or through our anonymous ftp, or through CD-ROM production or through the IRIS/SPYDER system for large earthquakes. In the near future easier ways will be available, such as autoDRM (automatic Data Request Management) and NetDC requests (Networked Data Centers, protocol proposed by the IRIS DMC of Seattle).

The FDSN Archive at the IRIS Data Management Center

In August of 1990, the IRIS Data Management Center (IRIS DMC) was designated as the first FDSN Data Center. Since that time the IRIS DMC has also come to be known as the FDSN Archive. As the FDSN Archive, all member networks, through their own local Network Data Centers, routinely send data to the IRIS DMC. At the present time we have received data from seven member networks. These include: CNSN (Canada); CDSN (China); GEOSCOPE (France); Graefenberg (Germany); IRIS GSN (U.S.A.); MEDNET (Italy); POSEIDON (Japan). In addition to acting as the FDSN Archive, the IRIS DMC is responsible for archiving and distributing data from several sources. The Global Seismographie Network (GSN) and the Program for Array Seismic Studies of the Continental Lithosphere (PASSCAL) and the Joint Seismic Program (JSP) are three IRIS programs that presently send data to the IRIS DMS. The DMC also archives data from some regional networks in the United States and in the Former Soviet Union (FSU). The DMC is one component of a larger Data Management System (DMS) consisting of several components including two Data Collection Centers (DCCs), one Data Management Center (DMQ, a DMC Host at the University of Washington, a Wave form Quality Center (WQC), and the Moscow Data Analysis Center (MDC) in Russia.

Rapid determination of global moment‐tensor solutions

In an effort to improve data services, the National Earthquake Information Center has begun a program, in cooperation with the Incorporated Research Institutions for Seismology Data Management Center (IRIS DMC), to produce rapid estimates of the seismic moment tensor for most earthquakes with a body‐wave magnitude of 5.8 or greater. Although this program is still undergoing testing and fine‐tuning, an estimate of the moment tensor can usually be produced within 20 minutes of the arrival of the broadband P‐waveform data from the IRIS DMC. Although the speed with which this data can be obtained varies, in many cases a solution can be obtained within two hours of the earthquake. These solutions do not vary significantly from the final solutions determined using the entire network. Because of the manner in which the data and the synthetic seismograms are aligned, the method is insensitive to the effects of timing errors, epicentral mislocation, and lateral heterogeneity in earth structure. This procedure was implemented in May 1993; the results from that month are presented here.

Passcal instrument performance during the Tibetan Plateau Passive Seismic Experiment

Summary The PASSCAL instrumentation performed very well in the Tibetan Plateau Seismic Experiment. This experiment has demonstrated the viability of recording high-quality broadband data at temporary sites in extreme environments. It also highlights some areas where further development is needed. Primarily, more effort is needed to develop more versatile triggering options for the PASSCAL instruments. Such developments could both increase the instrument's success at recording low magnitude teleseismic events for travel-time studies and save disk space when recording local events, thus further increasing the feasibility of long deployments in remote regions. Although the use of the PASSCAL instrument's calibration circuitry for sensor recentering is a valuable technique, more experience is needed in the construction of sensor pads to minimize tilt problems that require site visits to relevel the seismometer such as we experienced at a few sites in the winter. This may also lead to improved low-frequency noise levels, although signals with periods greater than 200 sec can be recovered from these sites. The most exciting aspect of the data we have collected is its broad frequency content and spatial density. We anticipate that this type of experiment will be increasingly useful in the study of lithospheric interactions as well as deep Earth structure. This data was delivered to the IRIS Data Management Center in early September 1993 and is available to the community. Two other broadband passive-seismic experiments, the Baikal Rift experiment (Gao et al. 1992) and the Rocky Mountain Front experiment (Sheehan et al. 1992) should be delivered to the IRIS DMC in the Fall of 1993 as well. Temporary broadband seismic experiments represent an extension of the permanent Global Seismic Network (GSN). We encourage the seismological community to incorporate these data into any research using GSN data in order to maximize the potential utility of this new mode of seismic recording.