In response to a reported landslide incident which occurred on July 29, 2009, at the Rizal Provincial Sanitary Landfill Site located in Rodriguez, Rizal, a composite investigation team from the Mines and Geosciences Bureau Central and Region IV-A Offices were immediately dispatched to look into the cause or causes of the phenomenon. The investigation team was composed of geologists from said MGB offices led by MGB Region IV-A OIC Regional Director Miguel C. Fernandez, Jr., personnel from the Office of Civil Defense led by Mr V. Tomazar, Regional Director of OCD Region IVA, and elements of the local police of Rodriguez led by their Chief of Police.

According to eyewitnesses and residents of the surrounding areas, the landslide incident occurred at around 11 PM and was allegedly  preceded by a deafening explosion. During the site visit the following were observed by the investigation team:
•    Landslide comprises of garbage and earth materials from the landfill site      including concrete manholes.
•    The landslide materials has buried a portion of the river beside the landfill site
•    The landslide created some damming and ponding of water at the upper portion of the river
•    The operator of the landfill site is already digging a channel along the slide materials to draw the water from dammed portion of the river

Preliminary investigation indicates that, the landslide incident could be probably due to slope failure of the saturated earth-fill materials which was erected to prevent the garbage from falling down the nearby river.
The explosion that was heard was probably due to sound that was created during sliding of the garbage and earth materials or explosion of accumulated methane gas within the garbage materials. A more comprehensive and detailed investigation was recommended to study the cause of the landslide incident.