EPSL paper on slow earthquake in the Sea of Marmara

We recently published a paper in Earth and Planetary Science Letters entitled “Slow strain release along the eastern Marmara region offshore Istanbul in conjunction with enhanced local seismic moment release”.

The paper was quite widely commented in a GFZ press release, as well as in the Science Daily and Phys.org.

Full reference:

Martínez-Garzón, P., M. Bohnhoff, D. Mencin, G. Kwiatek, G. Dresen, K. Hodgkinson, M. Nurlu, F. T. Kadirioglu, and R. F. Kartal (2019). Slow strain release along the eastern Marmara region offshore Istanbul in conjunction with enhanced local seismic moment release, Earth and Planetary Science Letters 510, 209–218, DOI: 10.1016/j.epsl.2019.01.001.


We analyze a large transient strainmeter signal recorded at 62.5 m depth along the southern shore of the eastern Sea of Marmara region in northwestern Turkey. This region represents a passage of stress transfer from the Izmit rupture to the Marmara seismic gap. The strain signal was recorded at the Esenkoy site by one of the ICDP-GONAF (International Continental Drilling Programme – Geophysical Observatory at the North Anatolian Fault) strainmeters on the Armutlu peninsula with a maximum amplitude of 5 microstrain and lasting about 50 days. The onset of the strain signal coincided with the origin time of a MW 4.4 earthquake offshore Yalova, which occurred as part of a seismic sequence including eight MW ≥3.5 earthquakes. The MW 4.4 event occurred at a distance of about 30 km from Esenkoy on June 25th 2016 representing the largest earthquake in this region since 2008. Before the event, the maximum horizontal strain was subparallel to the regional maximum horizontal stress derived from stress inversion of local seismicity. During the strain transient, we observe a clockwise rotation in the local horizontal strain field of about 20°. The strain signal does not correlate with known environmental parameters such as annual changes of sea level, rainfall or temperature. The strain signal could indicate local slow slip on the Cinarcik fault and thus a transfer of stress to the eastern Marmara seismic gap.

Paper on SHEER project database within EPOS system

Some months ago Szymon Cielesta has published a paper that presents the development of SHEER database and its implementation in EPOS TCS Anthropogenic Hazard system.


Cielesta, S., B. Orlecka-Sikora, M. Staszek, P. Urban, D. Olszewska, E. Ruigrok, S. Toon, M. Picozzi, G. Kwiatek, S. Cesca, J. A. López Comino, C. Isherwood, N. Montcoudiol, and J. Jarosławski (2018). SHEER “smart” database: technical note. Acta Geophysica. DOI: 10.1007/s11600-018-0205-3


The SHEER database brings together a large amount of data of various types: interdisciplinary site data from seven independent episodes, research data and those for the project results dissemination process. This concerns mainly shale gas exploitation test sites, processing procedures, results of data interpretation and recommendations. The smart SHEER database harmonizes data from different fields (geophysical, geochemical, geological, technological, etc.), creates and provides access to an advanced database of case studies of environmental impact indicators associated with shale gas exploitation and exploration, which previously did not exist. A unique component of the SHEER database comes from the monitoring activity performed during the project in one active shale gas exploration and exploitation site at Wysin, Poland, which started from the pre-operational phase. The SHEER database is capable of the adoption of new data such as results of other Work Packages and has developed an over-arching structure for higher-level integration.

Update 3.8.1 to foci software package

New version (3.8.1) of foci software package has been released recent week. This version brings some new features that will be developed in next months:

– Introduction of inelastic attenuation correction in calculation of full seismic moment tensor.
– Multiple corrections to preferences window.
– Introduction of foci package into github version control system
– Code cleanup.

The polish version of foci website has been also rearranged and refurbished. This is the first step to translate this page into english.

Building up page on The Geysers studies

The Geysers represents a unique site for analysis of induced seismicity. This vapor-dominated geothermal field is located about 120 km north of San Francisco where the geothermal power production is performed for more than 50 years. Currently, The Geysers is the world’s largest geothermal field operated by Calpine and spanning an area of around 78km2 with the nominal capacity of 1517 MW. It is also an area of intensive induced seismic activity, with the largest event reaching magnitude 5.0. The seismicity is recorded with an extensive seismic monitoring networks operated by Lawrence Berkeley National Laboratory, and broadband regional network.

The availaibility of high quality data triggered our interest in understanding seismo-mechanical processes in this reservoir. This resulted in a number of publications, that I decided to gather in one place – The Geysers resesarch page.