Services & Methodology

Six methods that build one picture of the ground

Every engagement is scoped to the question that matters at that stage — regional hazard for site selection, near-surface imaging for foundation design, liquefaction potential for seismic zones.

REGIONAL · KM SCALE

PSHA / DSHA

Probabilistic Seismic Hazard Analysis considers all credible earthquake sources and produces hazard curves and Uniform Hazard Spectra for a chosen return period. Deterministic Seismic Hazard Analysis evaluates the Maximum Credible Earthquake on the controlling fault for a conservative, worst-case design basis. Used together, they satisfy IS 1893 design requirements for ordinary buildings through critical infrastructure.

0–30 M DEPTH

MASW

Multichannel Analysis of Surface Waves estimates the shear-wave velocity profile from surface measurements, without boreholes. The resulting Vs30 value determines IS 1893 site class and feeds directly into site response analysis.

0–100 M DEPTH

ERT

2D Electrical Resistivity Tomography maps subsurface resistivity contrasts tied to lithology, moisture and weathering — useful for identifying aquifers, fill boundaries, and depth to bedrock across a site.

NEAR-SURFACE

GPR

Ground-Penetrating Radar images shallow subsurface features non-invasively — buried utilities, voids, foundations and fill boundaries — ahead of excavation or intrusive investigation.

SITE SPECIFIC

Liquefaction assessment

SPT-based comparison of Cyclic Resistance Ratio against Cyclic Stress Ratio establishes liquefaction potential by depth. Results are integrated into a Liquefaction Potential Index (LPI) and mapped across susceptibility classes from very low to very high.

REGIONAL GIS

GIS hazard zonation

Seismic hazard, fault proximity, soil conditions, topography, land use and infrastructure proximity are standardized, weighted using the Analytic Hierarchy Process, and overlaid in GIS to produce a composite site suitability map.

Reference material

How each method is applied

The following reference sheets outline our working methodology for the four most-requested assessment types.

Six-step site screening workflow for seismic hazard assessment, from regional seismicity screening through to a suitable / conditionally suitable / not suitable decision. — Site screening workflow — from regional seismicity to a site suitability decision, ahead of detailed PSHA/DSHA and geotechnical investigation.

Comparison of PSHA and DSHA methodology, deliverables and recommended design basis by structure type per IS 1893. — PSHA vs. DSHA — methodology overview and recommended design basis for ordinary buildings, important buildings and critical infrastructure.

Liquefaction susceptibility mapping methodology showing factors considered, susceptibility classes, and GIS workflow. — Liquefaction susceptibility mapping — factors, classification, and GIS-based workflow used to generate a susceptibility map.

Integrated shallow geophysical subsurface mapping using seismic refraction, MASW, ERT and microtremor HVSR methods. — Integrated shallow geophysical mapping (0–100 m) — combining refraction, MASW, ERT and HVSR for a single subsurface interpretation.

Compliance

Standards and credentialing

A common question we get: which certification do we need before commissioning a survey? Here's the accurate picture.

Applicable standard

IS 19235:2025

The relevant geotechnical services standard. It is compliance-based rather than a stamp certification — work is expected to conform to it, not be separately "certified" against it.

In progress

NABL accreditation

The correct accreditation pathway for a survey/testing services firm — not BIS. NABL accreditation is the recognized route for demonstrating laboratory and testing competence in India.

Registered

GeM registration

Government e-Marketplace registration, enabling participation in government and public-sector procurement for site screening and geotechnical services.

Optional

ISO 9001:2015

Quality management system certification — an optional but recognized signal of process maturity for larger EPC and institutional clients.

Note: BIS certifies products, not survey service firms — a common point of confusion when procuring geotechnical services.

Not sure which method fits your site?

Send us the location, structure type and project stage — we'll recommend the right combination.

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