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Marcus Herrmann

PhD student

Marcus Herrmann
Swiss Seismological Service (SED)
ETH Zürich
Marcus Herrmann
NO FO 55.1
Sonneggstrasse 5
8092 Zürich

  +41 44 633 91 72
  

I started at the SED as an intern—and with a particular interest: communicating the potential impact of earthquake shaking through seismic risk. I quantified the seismic risk in terms of human loss; I process varied data in a system of four models (viz. seismicity, hazard, risk, and loss model). Since our group works on earthquake forecasting too, I approached time-varying (i.e. short-term) loss forecasts. With this concept, I searched for ways to improve risk communication to decision-makers and to the public during a seismic sequence. I dedicated the first part of my PhD to that research topic.

 

My current research focusses on the long-term behavior of induced seismicity at the terminated Enhanced Geothermal System (EGS) in Basel. Seismic monitoring at this site is running for more than ten years and covers several stages: hydraulic pre-stimulation in November 2006, 6-day-long fluid injection for reservoir creation in December 2006 with subsequent injection stop after a widely felt ML3.4, ultimate shut-in (closure) of the borehole in 2011, and renewed increase of seismicity from mid-2012 onwards.

The existing catalog is incomplete. To analyze seismicity of the geothermal reservoir over its whole lifetime, I need to produce a seismic catalog with homogeneous detection sensitivity and consistent magnitude estimates. I apply the template-matching technique that takes advantage of waveform similarity: scanning with waveforms of known earthquakes for finding unknown earthquakes (especially smaller events) in the 10-year-long seismic recordings. For best sensitivity, I scan the data of the deepest borehole station (OTER2, 2.7km depth) which is very close (1.5–2.5km) to the ~4.5km-deep reservoir.

Compared to the previous catalog, we find ~ten times as much events (>100’000). The high temporal and spatial resolution of the produced catalog allows us to analyze the statistics of the induced Basel earthquakes in great detail. We resolve spatio-temporal variations of the a- and b-value that have not been identified before, enabling us to derive the first high-resolution temporal development of the seismic hazard for the Basel EGS reservoir for the last 10 years.

I have also started to extend such analyses to natural sequences in Switzerland (see the news section and the news archive).

Zechar, J.D., Herrmann, M., van Stiphout, T. and Wiemer, S. (2014). Forecasting Seismic Risk as an Earthquake Sequence Happens. In: M. Wyss: Earthquake Hazard, Risk and Disasters. Elsevier. doi: 10.1016/B978-0-12-394848-9.00007-9

Gulia, L., Tormann, T., Wiemer, S., Herrmann, M. and Seif, S. (2016). Short-term probabilistic earthquake risk assessment considering time-dependent b-values. Geophysical Research Letters 43, 1100–1108. doi: 10.1002/2015GL066686

Herrmann, M., Zechar, J.D. and Wiemer, S. (2016). Communicating time-varying seismic risk during an earthquake sequence. Seismological Research Letters 87(2A), 301–312. doi: 10.1785/0220150168

  • GEOBEST-CH
  • GEOTHERM-2
  • Risk, safety and societal acceptance (SCCER SoE T4.1)
  • Risk Governance of Deep Geothermal and Hydro Energy (SCCER-SoE)
  • detect-µ