The alluvial flats around the Burnett River in Bundaberg behave very differently from the volcanic-derived soils near the town centre. In the river corridor, soft Holocene clays can amplify ground motion at low frequencies, whereas the older basalt profiles closer to Woongarra show much stiffer responses. An HVSR microtremor survey in Bundaberg captures that natural resonance directly, measuring the H/V spectral ratio from ambient vibrations. It is a quick, non-invasive way to identify fundamental site frequency without drilling. For projects on the coastal plain, we often pair the HVSR results with a subrasante vial assessment to understand how the subgrade will behave under cyclic loading.
The HVSR microtremor survey in Bundaberg captures natural soil resonance directly, revealing the fundamental frequency that governs seismic site response.
Methodology applied in Bundaberg
Key parameters derived from the survey include:
- Fundamental resonance frequency (f0) in Hz
- Peak H/V amplitude (amplification factor)
- Estimated depth to seismic impedance contrast
- Site class correlation per AS 1170.4
Typical technical challenges in Bundaberg
In Bundaberg, many times we see that the main risk is not the peak ground acceleration itself, but the resonance coupling between a soft soil layer and a medium-rise building. A 3-storey structure has a natural period around 0.3–0.5 seconds, and if the soil resonates at 2–3 Hz, the amplification can double the seismic demand. An HVSR microtremor survey in Bundaberg identifies those critical frequencies before design. Without it, engineers may under-design for low-frequency shaking and over-design for high-frequency motion, leading to either unsafe or uneconomic structures.
This service complements our laboratory testing work for a complete project analysis.
Our services
We offer three complementary HVSR survey scales to match different project budgets and site conditions in Bundaberg.
Single-station HVSR survey
A rapid 60-minute measurement at one location to determine the fundamental frequency and site class. Ideal for small residential projects or a quick check before a geotechnical borehole program.
Multi-station array survey
Five to ten stations deployed along a profile or grid to map lateral variations in resonance frequency. Suitable for subdivisions, road corridors, and medium-rise developments where soil conditions change across the site.
Integrated HVSR + MASW survey
Combining microtremor measurements with active MASW to obtain both the resonance frequency and a Vs30 profile. This is the preferred approach for AS 1170.4 site classification on complex ground.
Frequently asked questions
What is the HVSR microtremor survey method?
The HVSR (horizontal-to-vertical spectral ratio) method, also known as the Nakamura technique, records ambient ground vibrations using a three-component seismometer. The ratio of horizontal to vertical spectra reveals the fundamental resonance frequency of the soil column. It is a passive seismic method that requires no artificial energy source.
How much does an HVSR survey in Bundaberg cost?
For a standard single-station survey in Bundaberg, the cost typically ranges between AU$2,120 and AU$3,570. Multi-station arrays or integrated surveys with MASW are higher due to additional field time and processing. Contact us for a quote tailored to your specific project scope and number of stations.
How is HVSR different from MASW or ReMi?
HVSR measures the natural resonance frequency of the soil using passive ambient vibrations only. MASW and ReMi require an active seismic source (sledgehammer or weight drop) to generate surface waves. HVSR is faster and less intrusive, but it does not provide a direct Vs30 value. MASW or ReMi are needed when a shear-wave velocity profile is required for site classification.
Do I need an HVSR survey for a single residential house in Bundaberg?
For a standard single-storey house on stiff ground, an HVSR survey is usually not mandatory. However, if the site is on soft alluvium near the Burnett River or if you are building a two-storey or three-storey structure, the survey helps identify potential resonance issues. Local council may request it for developments in known liquefaction-prone zones.