On 28 March 2025, a moment magnitude Mw 7.7 earthquake struck central Myanmar, exposing the second and third largest cities of Myanmar, Mandalay and Naypyitaw, respectively, to intensity IX shaking and causing extensive damage and more than 3000 fatalities . The event occurred along the Sagaing Fault, a major right-lateral strike-slip fault that slips at ∼2 cmyr-1 and accommodates about half of the transverse motion between the Indian and Sunda plates . Myanmar is a seismically active region with a high seismic hazard , and specifically, the fault segment between Mandalay and Naypyitaw has been identified as a seismic gap . Its current national seismic monitoring network MM;, which is operated by the Department of Meteorology and Hydrology (DMH) of Myanmar, was initiated in 2016 with the installation of five seismic stations with the support of the US Geological Survey and USAID . With the support of the Indian National Centre for Ocean Information Services (INCOIS) and the Regional Integrated Multi-hazard Early Warning System (RIMES, based in Thailand), an additional four stations were added (Fig. ). For several years, the Earth Observatory Singapore operated a permanent broadband network of 30 stations e.g.,, which was completed in 2024. Additionally, several temporary networks of shorter recording times of 1–2 years have provided information on the seismic structure e.g.,. In spite of these efforts, Myanmar's permanent seismological infrastructure remains sparse, and all networks suffered station outages due to travel restrictions caused by COVID-19 and the political situation.

As part of a long-term collaboration between the GFZ German Research Centre for Geosciences

Current name: GFZ Helmholtz Centre for Geosciences.

For more than a decade, the GFZ and the DMH of Myanmar have been developing a long-term partnership to strengthen seismic monitoring, hazard assessment, and scientific capacity building in Myanmar. The first contacts were established in 2010 with initial cooperation within joint regional seismological initiatives. In 2016, GFZ and DMH jointly organized the International Training Course on seismology and seismic hazard assessment (ITC) in Naypyitaw (https://www.gfz.de/fileadmin/gfz/sec21/pdf/ITKurse/2016Myanmar/web_programme.pdf, last access: 17 July 2025); also see . During the training course, scientists from Myanmar and the wider Southeast Asia region were trained in seismology, seismic data analysis, hazard assessment, and risk mitigation. For the first time, the installation of a permanent seismic station (NPW) and a SeisComP system for acquisition and analysis were added as additional components to the training program and handed over to the local hosting institution at the end of the training (Fig. ). The standard program of the ITC was thus complemented with transfer not only of hardware but also of additional technical know-how, building on the lessons learned from establishing and maintaining the GEOFON network . During the ITC, general introductory lectures on SeisComP introduced all participants to the basic use and focused on how to obtain relevant metadata and waveform data from other data archives operated by EIDA and EarthScope IRIS; the participants also practiced interactive event location using the SeisComP graphical user interface with simulated playbacks.

The later part, dedicated to DMH staff only, went into more detail on the practicalities of installing SeisComP and integrating into the real-time workflow the new seismic station NPW at DMH, other Myanmar National Seismic Network (FDSN network code MM) stations , which are acquired from a separate local acquisition server, as well as stations from other networks in Southeast Asia and the rest of the world. The availability of high-quality strong-motion recordings, particularly from near-fault stations such as NPW, provides valuable data for advancing our understanding of seismic hazard and for informing future engineering design and mitigation efforts in the region.

As a further outcome of the deeper cooperation fostered during the workshop, a temporary seismic array consisting of 30 broadband stations was deployed in northern Myanmar , in close cooperation with other international activities from the US and Singapore , and with consideration of the temporary Chinese experiments conducted in Myanmar shortly before . During the preparation and deployment of the array, additional spare hardware was handed over to DMH, and maintenance and capacity-building activities were also carried out at the NPW co-operated station.

The DMH/GEOFON seismic station in Naypyitaw (NPW) is the first station in the GE network that was established during an ITC event. The operation of this station, like that of nearly all the other GE stations, is based on a clear commitment from the partners, in this case, DMH, to commit to long-term joint operation and ownership by providing local facilities and technical expertise in case maintenance actions are needed. In return, GEOFON provides hardware as needed, capacity building (in this case embedded in the ITC), data curation and preservation, and a long-term commitment to joint operations, which includes remote support during maintenance actions, if required, and the shipping of replacement parts that cannot be obtained locally. The NPW station is located in Naypyitaw, Myanmar, within the DMH facilities at 19.78° N and 96.14° E, at an elevation of 158 m. It is only 2.6 km from the rupture plane and 246 km from the epicenter of the 2025, Mw 7.7 mainshock (Fig. a).

To prepare for the installation, DMH provided a shelter (Fig. b) with a 2 m deep vault adjacent to it. They further contributed an existing Güralp CMG-3ESPC 30 s sensor, with a continuous power supply and connectivity via the local network of the seismology department building. During the preparatory work, which took place in early 2016, GFZ provided additional Güralp hardware, including a Fortis accelerometer, a DM24 digitizer, and an EAM local computer unit, which enables direct SeedLink streaming (Fig. ). In addition to the seismological hardware, GFZ provided a mobile router for backup communication via a protected virtual private network (VPN) link and a power control module. The station is powered by the local mains power with an additional under-voltage protected battery as a buffer, to keep the station running for a few days in case of a power outage. As the vault was flooded just before installation, the broadband sensor, the accelerometer, and all the other hardware were housed in the shelter (Fig. b and c). The mode of the power spectral density (Fig. ) falls within the lower and upper limits of the New Noise Model proposed by . In particular, it is less than 10–20 dB from the lower limit for periods longer than 1 s. Since the sensor showed reasonable noise levels for the wide band sensor, it was decided to leave the sensors in the shelter rather than move them to the vault and risk damage from repeated flooding.

In terms of noise level (Fig. ), the station is well suited for local, regional, and teleseismic monitoring, despite its location in an area of urban activity. The broadband sensor allows clear identification of the primary and secondary microseismic peaks. The increasing local anthropic noise is clearly visible for periods shorter than 1 s. The strong-motion sensor performed as expected for periods shorter than 1 s, enabling the dynamic range extension to record large near-fault events up to 2g, which is the full scale to which it is set.

Therefore, although NPW is not installed in a remote and quiet area, it can be considered a good-quality station for intermediate and long periods. In our view, it represents a good compromise between quality and availability in a region with sparse coverage; the setup was discussed and agreed upon with the local partners and adapted to the actual capacity and needs of long-term operation. In fact, since its installation, the station has been operating with several intervals where the data flow was interrupted but was always restored by DMH staff with only remote support from the GEOFON maintenance team. The overall data availability since installation is ∼80 %. Figure c shows the availability for the last 4 years (since 1 January 2021), with a large gap between 13 October 2024 and 10 February 2025 with an overall average availability of 82 % for the given period (90 % since January 2025 and 100 % from 28 March 2025 (day of the mainshock) to 7 April 2025). The station's timing quality has been unstable since installation despite attempts to change parts of the GPS hardware. For users of these data, we further note that the timing quality reported by the data logger seems to be consistent with the time since last lock until the beginning of the large gap in October 2024 (Fig. d), but when data flow was restored in February 2025, the timing quality was no longer consistently reported and can no longer be considered a reliable indicator. Nevertheless, sporadic GPS locks occurred every few days, with the last known GPS lock before the mainshock on 23 March 2025. Triggered by the observations of growing residuals in arrival times, we investigated the timing of NPW using ambient seismic noise cross-correlation of the HH channels with the neighboring stations MM.NGU, MM.TGI, and TM.MHIT (Fig. ). Correlations of NPW's HHZ and HHN channels with NGU provide the most stable estimates of the clock offset, as illustrated in Fig. . We find that NPW lost GPS synchronization on 19 March at 04:00 UTC (±18 h) when the clock started to drift linearly with a rate of 1.14×10-6 ± 6.6×10-8, i.e., 98.6 ± 5.7 msd-1 (regression coefficient r2=0.87). At the time of the mainshock, the accumulated clock error was 775 ± 40 ms. Observations with other stations confirm these findings, however, with less accuracy.

The NPW station plays a crucial role in regional and global seismic monitoring, providing valuable data for seismological research and contributing to earthquake hazard studies by improving the completeness of earthquake catalogs. The station is in the International Registry of Seismograph Stations and has contributed to more than 3000 P-phase observations at the ISC , see https://www.isc.ac.uk/cgi-bin/stations?stacode=NPW (last access: 17 July 2025).

Following the MW 7.7 earthquake on 28 March 2025, the contact was initially lost a few seconds after the P onset. The condition of the station was unknown to GEOFON staff at that time. The station started transmitting data again on 1 April 2025, 4 d after the earthquake. By remote connection, it was confirmed that the station had continued recording throughout and that only data transmission was lost during the data gap, such that it was possible to backfill the data holdings. Given the amount of damage incurred to the power and communications infrastructure, the continuous operation of the station and quick restoration of connectivity are remarkable.

Given low prior usage of the strong-motion data, GEOFON staff identified a serious metadata issue affecting three strong-motion components; in the wake of clarifying this issue, a more subtle issue was also identified with the metadata of the broadband instruments. As a result, a public warning to data users was issued immediately (https://geofon.gfz.de/forum/t/metadata-for-ge-npw/32635, last access: 17 July 2025). As soon as the open questions could be clarified, which required checking with the manufacturer, the metadata were updated and a notification was issued to warn users to re-download the metadata.

The station proved to be instrumental in recording this seismic event, providing critical data for the rapid understanding of some basic characteristics of the earthquake, as presented in the following sections of this article.

In order to evaluate the quality of the data and metadata of station NPW and to characterize the recordings of the 2025 sequence from an engineering seismology perspective, we use the stream3segment software to download the seismic waveform data from the GEOFON node (https://geofon.gfz.de/fdsnws/dataselect/1/, last access: 17 July 2025) of EIDA (https://www.orfeus-eu.org/data/eida/, last access: 17 July 2025) and populate a local PostgreSQL database. Station metadata are retrieved from the GEOFON station service (https://geofon.gfz.de/fdsnws/station/1/, last access: 17 July 2025). Event metadata are retrieved from the European-Mediterranean Seismological Centre (EMSC) event web service (https://www.seismicportal.eu/fdsn-wsevent.html, last access: 17 July 2025) to compile a catalog of earthquakes with a magnitude greater than 3, occurring since 2021, within a radius of 5.5° from station NPW. From the continuous waveform data, we extract 5 min windows centered on the theoretical P arrival of each event computed considering the AK135 global velocity model .

To assess the quality of the data and evaluate their potential for both seismological applications, such as constraining the spatial and temporal evolution of the rupture process and engineering seismology studies, we conducted a series of analyses based on the mainshock recordings:

Broadband displacement and static offset. The NPW recording of the Mw 7.7 mainshock provides the rare opportunity to investigate near-fault ground motion data. Figure  shows the static displacement obtained through double integration of the unfiltered, instrument-corrected acceleration. Before each integration, a linear trend was removed from the entire time window. The trend was based on straight-line fitting of 5 min of noise immediately preceding the P onset. To determine the static offset and to flatten the coda trace, a simple quadratic function was fit to the first 2 min of the double-integrated data after the displacement stabilized. The linear and quadratic terms were then removed from the data. The retrieved static displacement on the north–south (NS) component, which is almost parallel to the fault strike, is 1.6 m, whereas on the east–west (EW), it is about -0.13 m. The static displacement offset measured along the fault parallel component (i.e., the NS one), which corresponds to unidirectional long-period velocity pulse, is known in the engineering seismology context as fling-step e.g.,.

For the following analysis, each trace is detrended and 5 % tapered at both ends before being band-pass filtered using a zero-phase (acausal), fourth-order Butterworth filter. For the mainshock, the high-pass corner frequency is fixed at 0.02 Hz, while for aftershocks, it is adapted based on magnitude . The low-pass corner frequency is set to 40 Hz. The instrumental response is removed, and the resulting acceleration time series are integrated to obtain velocity. Finally, acceleration and velocity response spectra are computed assuming 5 % critical damping.

Peak ground acceleration and velocity. To analyze the earthquake recordings from an engineering seismology perspective, Fig.  presents the high-pass filtered acceleration and velocity time histories. The peak ground accelerations (PGAs) for the vertical (Z), NS (fault-parallel), and EW (fault-normal) components are 10.53, 6.10, and 5.63 ms-2, respectively. Notably, the vertical component exhibits the highest PGA, exceeding those of both horizontal components.

Finally, since station NPW has been continuously recording since the onset of the seismic sequence, numerous high-quality aftershock recordings are now available in the archive. Figure  presents the European-Mediterranean Seismological Centre (EMSC) locations of the mainshock and 61 aftershocks with magnitudes greater than 3.0, recorded up to 7 April 2025. Among these, Fig.  also shows the processed acceleration and velocity time histories of a well-recorded Mw 6.7 aftershock that occurred just 12 min after the mainshock, at 06:20:54 UTC, approximately 220 km from station NPW. Another example is the mb 5.1 aftershock recorded on 29 March 2025, at 09:20:47 UTC, located only 12.3 km from the station. These events highlight the value of the NPW station for capturing both near-fault and far-field ground motions throughout the sequence. The 61 events are part of the dataset used to investigate the site resonances following the approach by .

Site resonance frequencies. Figure  shows the broadband resonance curves at station NPW, computed using the time-frequency resonance analysis method adapted from . We selected aftershock records with PGA ranging from 1 to 10 cms-2, recorded by accelerometers up to 7 April 2025, resulting in a dataset of 20 events with magnitudes between 3.5 and 6.7. For each event, we applied a time window of 15 s for magnitudes ≤6.0 and 20 s for magnitudes >6.0, beginning 20 % of the window duration before the PGA time and extending 80 % beyond it. The Stockwell transform was then applied to the windowed time series of the derivative of acceleration, acceleration, velocity, and displacement. The squared spectral amplitudes, representing signal energy over time, were normalized between 0 and 1. We then computed three percentiles along the time axis to obtain a smooth representation of energy distribution in the frequency domain, referred to as the resonance curve. The peaks of the curves serve as proxies for the frequencies of linear site amplification but housing effects cannot be ruled out. The station has a predominant resonance frequency around 12–13 Hz. Although this peak is dominant, a secondary peak around 7–8 Hz is also present in the resonance curve, albeit somewhat obscured by the taller primary peak. Additionally, relatively smaller and less prominent peaks are observed at 2.5–3 Hz, 1.4–2 Hz, and approximately 0.9–1.1 Hz.

Software and processed data are available at Zenodo under 10.5281/zenodo.15921214 .

The installation of station NPW was made possible through a collaborative effort between the Department of Meteorology and Hydrology (DMH) in Naypyitaw and the GFZ Helmholtz Centre for Geosciences. Similar to other initiatives, like the upgrade of the MM network as part of an effort supported by the USGS and USAID , this collaboration underscores the critical role of capacity building in supporting the development of high-quality, open-access seismic data that can serve both national monitoring efforts and the global scientific community. By strengthening local expertise, infrastructure, and collaborative networks, such initiatives help establish and sustain robust seismic monitoring systems that provide valuable observations for advancing earthquake science and hazard assessment. In the case of the Mw 7.7 Myanmar earthquake sequence in 2025, NPW is the only station to provide near-fault, on-scale recordings of the mainshock and the largest aftershocks. It thus adds a rare example of a near-fault record of a supershear rupture to the global strong-motion databases. As such, the NPW near-fault dataset presented in this study not only supports fundamental research aimed at improving our understanding of earthquake processes and seismic hazard but also informs practical strategies for risk mitigation, urban planning, and resilient infrastructure design in vulnerable regions.