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About me

 I am an earthquake seismologist. The broad goal of my research is to better understand the physics of earthquakes, the processes that control them, and their associated hazards by examining a wide spectrum of fault slip across a broad range of spatial and temporal scales. I use seismograms, ground vibrations created by earthquakes and recorded by seismometers, as my primary tool. Some of my focus areas are seismic array techniques, machine learning and their applications in imaging earthquakes — big and small, slow and fast. In addition, I work on aftershock dynamics, fault structure, induced earthquakes and sustainability.


  • Earthquakes source physics

  • Different flavours of earthquakes (slow, fast and in between)

  • Observational seismology

  • Aftershock dynamics

  • Fault structure

  • Induced earthquakes

  • Geo-energy

  • Earthquake hazards and sustainability

  • Array seismology

  • Machine learning


Abhijit Ghosh

(aka Obi)
Associate Professor of Geophysics
Department of Earth and Planetary Sciences
University of California, Riverside


Professional Profile


PhD in Geophysics

Department of Earth & Space Sciences, University of Washington, Seattle, WA, USA


MS in Earth & Atmospheric Sciences (Geophysics)

School of Earth & Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA


MS in Geology

Department of Geology, University of Calcutta, Kolkata, India


BS in Geology (with Mathematics and Physics)

Department of Geology, University of Calcutta, Kolkata, India


Associate Professor

Earth and Planetary Sciences, University of California, Riverside, USA


Assistant Professor

Earth and Planetary Sciences, University of California, Riverside, USA


NSF-GeoPRISMS Postdoctoral Fellow

Earth and Planetary Sciences, University of California, Santa Cruz, USA


Research Associate

Earth & Space Sciences, University of Washington, USA


Junior Research Fellow

Geological Sciences, Jadavpur University, India

Recent Publications

Link to full article

Seismic tremor signals, also known as long-period, long-duration signals, have been reported in several locations where fluid injection for enhanced oil and gas exploration is taking place. However, the origin of these signals remains poorly constrained. We studied seismic tremor signals in Wellington Field, Kansas, using a seismic array during a carbon dioxide injection program. We show that these signals are generated

Link to full article

Slow earthquakes are an important part of a broad spectrum of the earthquake behavior. Yet, their underlying physics and connection to rest of the earthquake spectrum remain enigmatic. Taiwan is an area with complex geology hosting slow earthquakes. Still, their characteristics and relationship to other regular earthquakes are poorly understood. Using three years of high-quality seismic data, we have identified and located three discrete events known as very low-frequency earthquakes occurring deeper than the typical seismogenic zone in the earth crust. Our analyses show that these events modulate regular earthquakes in its vicinity. This relationship between the slow and fast earthquakes may be a result of fluid transfer from the deep to the shallow crust.

Link to full article

Various periodic external loading processes (e.g., snow, hydrological and atmospheric, earth tide and surface reservoir load, etc.) affect tectonic deformation and sometimes modulate seismicity in diverse tectonic settings. Small stress variations induced by external loads may influence the fault dynamics and destabilize fault zones. In this article, we report five cases of earthquake occurrence in the plate boundary and plate interior regions where such a destabilization seems to be operating. We test the possibility of resonance amplification assuming rate-and-state friction and look for the model parameters that could justify resonance destabilization. We find that frictional resonance destabilization is possible in regions that are near the stability boundary (velocity neutral areas). The critical slip distance for the evolution of friction is similar to laboratory estimates. In some cases, effective normal stress lower than the lithostatic stress have to be assumed for the model to be consistent with the observations, implying high pore pressure. We propose that crustal faults of conditionally stable frictional domains with anomalous pore pressure are sensitive to periodic stress perturbations by the external loading process.

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