Large pre-historical earthquakes leave traces in the geological and geomorphological record, such as primary and secondary surface ruptures and mass movements, which are the only means to estimate their magnitudes. These environmental earthquake effects (EEEs) can be calibrated using recent seismic events and the Environmental Seismic Intensity Scale (ESI2007). We apply the ESI2007 scale to the 1992 M S 7.3 Suusamyr Earthquake in the Kyrgyz Tien Shan, because similar studies are sparse in that area and geological setting, and because this earthquake was very peculiar in its primary surface rupture pattern. We analyze literature data on primary and secondary earthquake effects and add our own observations from fieldwork. We show that the ESI2007 distribution differs somewhat from traditional intensity assessments (MSK (Medvedev-Sponheuer-Karnik) and MM (Modified Mercalli)), because of the sparse population in the epicentral area and the spatial distribution of primary and secondary EEEs. However, the ESI2007 scale captures a similar overall pattern of the intensity distribution. We then explore how uncertainties in the identification of primary surface ruptures influence the results of the ESI2007 assignment. Our results highlight the applicability of the ESI2007 scale, even in earthquakes with complex and unusual primary surface rupture patterns.Geosciences 2019, 9, 271 2 of 17 may not be interpreted as a single earthquake. For example, the 2016 Kaikoura Earthquake in New Zealand with a magnitude of M W 7.8 ruptured at least twelve major crustal faults and produced highly variable primary surface ruptures [5]. It is unlikely that such complexity can be understood with paleoseismological methods, and the magnitude of the paleo-earthquake will probably be under-estimated. (iv) Incoherent and anomalous primary surface ruptures can not only be hard to detect, but may also cause problems when it comes to applying the empirical relationships. For example, the 1992 M S 7.3 Suusamyr Earthquake, Kyrgyzstan, broke the surface in two short sets of primary ruptures with a 25 km gap in between [6,7].One approach to overcome the problem of estimating paleo-earthquake magnitudes based solely on primary surface ruptures is the application of the Environmental Seismic Intensity Scale, ESI2007 [8][9][10]. In contrast to classical intensity scales, such as MSK (Medvedev-Sponheuer-Karnik) or MM (Modified Mercalli), the ESI2007 only uses effects on the environment to assign earthquake intensities. It, therefore, avoids the influence of building styles and the problem of saturation at high intensities, and allows applying the scale to paleo-earthquakes. The conversion of ESI2007 intensities to magnitudes, however, can only be based on a large set of modern case studies, which are currently being collected in the Earthquake Environmental Effects (EEE) catalogue hosted by ISPRA [11]. Preferably, this set of case studies should include earthquakes with different mechanisms, magnitudes, depths, tectonic and geological settings, distribute...